SECTION 6C1 - DRIVEABILITY AND EMISSIONS (C22NE MODELS)

SPECIFICATION

TIGHTENING SPECIFICATIONS

EMISSION CONTROL SYSTEM SCHEMATICS

DIAGRAMS AND SCHEMATICS

ECM PINOUTS

ECM PINOUT TABLE, 32-PI N BLUE CONNECTOR-ROW "J1"

ECM PINOUT TABLE, 32-PIN RED CONNECTOR-ROW "J 2"

COMPONENT LOCATOR

ENGINE COMPONENT LOCATOR TABLE

UNDERCARRIAGE COMPONENT LOCATOR TABLE

UNDERHOOD (U/H) FUSE AND RELAY PANEL

INSTRUMENT PANEL (I/P) FUSE BLOCK

DIAGNOSIS

STRATEGY-BASED DIAGNOSTICS

DTC STORED

NO DTC

NO MATCHING SYMPTOM

INTERMITTENTS

NO TROUBLE FOUND

VERIFYING VEHICLE REPAIR

Techline

GENERALSERVICE INFORMATION

OBD SERVICEABILITY ISSUES

FUEL QUALITY

NON-OEM PARTS

POOR VEHICLE MAINTENANCE

RELATED SYSTEM FAULTS

MAINTENANCE SCHEDULE

VISUAL/PHYSICAL ENGINE COMP ARTMENT INSPECTION

BASIC KNOWLEDGE OF TOOLS REQUIRED

SERIAL DATA COMMUNICATIONS

ON-BOARD DIAGNOSTIC (OBD)

ON-BOARD DIAGNOSTIC TESTS

COMPREHENSIVE COMP ONENT MONITOR DIAGNOSTIC OPE RATION

INPUT COMPONENTS

OUTPUT COMPONENTS

PASSIVE AND ACTIVE DIAGNOSIS TESTS

INTRUSIVE DIAGNOSIS TESTS

WARM-UP CYCLE

COMMON OBD TERMS

DIAGNOSTIC FOR CLOSED LOOP SYSTEM

FOR CLOSED LOOP SYSTEM

ENABLE CRITERIA

TRIP

THE DIAGNOS I TIC E XECUTIVE

DIAGNOSTIC INFORMATION

MALFUNCTION INDICATOR LAMP (MIL)

EXTINGUISH THE MIL

DATA LINK CONNECTOR (DLC)

READING FLASH DIAGNOSTIC TROUBLE CODES

READING DIAGNOSTIC TROUBLE CODES USING A TECH 2

CLEARING DIAGNOSTIC TROUBLE CODES

ON-BOARD DIAGNOSIS (SELF-DIAGNOSI S)

TECH 2 SCAN TOOL

GETTING STARTED

OPERATING PROCEDURE

VERIFYING VEHICLE REPAIR

READING DIAGNOSTIC TROUBLE CODES USING A SCAN TOOL

CLEARING DIAGNOSTIC TROUBLE CODES

DTC MODES

DTC INFORMATION MODE

CLEAR DTC INFORMATION

PRIMARY SYSTEM-BASED DIAGNOSTICS

FUEL CONTROL HEATED OXYGEN SENSORS (IF APPLICABLE)

HO2S HEATER

ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK

A/C CLUTCH CONTROL CIRCUIT DIAGNOSIS

ELECTRIC IGNITION SYSTEM DIAGNOSIS

EVAP CANISTER PURGE SOLENOID (IF APPLICABLE)

VISUAL CHECK OF THE EVAPORATIVE EMISSION CANISTER (IF APPLICABLE)

IDLE AIR CONTROL (IAC) VALVE

FUEL SYSTEM PRESSURE TEST

FUEL METERING SYSTEM CHECK

FUEL INJECTOR COIL TEST PROCEDURE AND

FUEL INJECTOR BALANCE TEST PROCEDURE

TEST DESCRIPTION

INJECTOR COIL TEST PROCE DURE (STEP1-6) AND

INJECTOR BALANCE TEST PROCEDURE (STEP7-11)

ENGINE CONTROL MODULE(ECM) DIAGNOSIS

MULTIPLE ECM INFORMATION SENSOR DTCS SET

ENGINE SCAN TOOL DATA DEFINITIONS AND RANGES

TYPICAL SCAN DATA VALUES

TEST CONDITIONS

2.2L/2.0L L-4 ENGINE

GENERAL DESCRIPTION (EVAPORATIVE (EVAP) EMISSION SYSTEM) (IF APPLICABLE)

EVAP EMISSION CONTROL SYSTEM PURPOSE

VAPOR CANISTER

EVAP CONTROL SYSTEM

RESULTS OF INCORRECT OPERATION

DIAGNOSIS

VISUAL CHECK OF CANISTE R

EVAPORATIVE EMISSION CANISTER PURGE CONTROL

SOLENOID VALVE CHECK (IF APPLICABLE)

GENERAL DE S CRIPTION

ECM DIAGNOSTIC TROUBLE CODES

SYMPTOM DIAGNOSIS

PRELIMINARY CHECKS

VISUAL/PHYSICAL CHECK

INTERMITTENT

HARD START SYMPTOM

SURGES AND/OR CHUGGLES SYMPTOM

LACK OF POWER, SLUGGISH OR SPONGY SYMPTOM

DETONATION/SPARK KNOCK SYMPTOM

ROUGH, UNSTABLE, OR INCORRECT IDLE,

STALLING SYMPTOM (FOR OPEN LOOP SYSTEM)

ROUGH, UNSTABLE, OR INCORRECT IDLE,

STALLING SYMPTON (FOR CLOSED LOOP SYSTEM)

IDLE CO CONCENTRATION CHECK AND ADJUSTMENT

POOR FUEL ECONOMY SYMPTOM

DIESELING, RUN-ON SYMPTOM

BACKFIRE S YMPTOM

CUTS, OUT, MISSES SYMPTOM

HESITATION, SAG, STUMBLE SYMPTOM

DEFAULT MATRIX TABLE

SERVICE P ROCE DURE DEFAULT STRATEGY

DEFAULT MATRIX TABLE

ENGINE CRANKS BUT WILL NOT RUN

FUEL SYSTEM ELECTRICAL TEST

FUEL SYSTEM DIAGNOSIS

MANIFOLD ABSOLUTE PRESSURE (MAP) OUTPUT CHECK

EVAPORATIVE EMISSIONS (EVAP) CANISTER PURGE

CONTROL SOLENOID VALVE CHECK

THROTTLE POSITION (TP) SENSOR CIRCUIT RANGE/PERFORMANCE PROBLEM

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=2 2)

THROTTLE POSITION (TP) SENSOR CIRCUIT LOW INPUT

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=2 1)

THROTTLE POSITION (TP) SENSOR CIRCUIT HIGH INPUT

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=1 3)

02 SENS O R CIRCUIT NOT READY DETECTED (IF APPLICABLE)

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=4 4)

02 SENSOR TOO LEAN (IF APPLICABLE)

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=4 5)

02 SENSOR TOO RICH (IF APPLICABLE)

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=1 4)

EINGINE COOLANT TEMPERATURE(ECT) SENSO R CIRCUIT HIGH INPUT

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=1 5)

ENGINE COOLANT TE MP ERATURE (ECT) S ENSOR CIRCUIT LOW INPUT

DIAGNOSI TC TROUBLE CODE (DTC) (FLASH DTC=16)

KNOCK SENSOR (KS) DISCONNE CTED MALFUNCTION

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=18) DIGITALLY

CONTROLED SIGNAL TO NOIS E ENHANCEME NT FILTER FAILURE

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=1 9)

CRANKSHAFT POSITION(CKP) SENSO R SIGNAL INCORRECT

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=2 4)

VEHICLE SPEED SENSOR (VSS) FAULT

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=3 3)

MANIFOLD ABSOLUTE PRESSURE (MAP) TOO HIGH

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=3 4)

MANIFOLD ABSOLUTE PRESSURE (MAP) TOO LOW

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=4 9)

SYSTEM VOLTAGE HIGH

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=6 9)

INTAKE AIR TEMPERATURE (IAT) SENSOR TOO HIGH

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=7 1)

INTAKE AIR TEMPERATURE (IAT) SENSOR TOO LOW

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=1 7)

INJECTOR CIRCUIT MALFUNCTION

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=4 1)

IGNITION COIL DRIVER "B" SHORT TO BATTERY

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=4 2)

IGNITION COIL DRIVER "A" SHORT TO BATTERY

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=6 3)

IGNITION COIL DRIVER "B" SHORT TO GROUND

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=6 4)

IGNITION COIL DRIVER "A" SHORT TO GROUND

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=3 5)

IDLE AIR CONTROL (IAC) ERROR

DIAGNOSTIC TROUBLE CODE (DTC) 56 (FLASH DTC=56)

CHECK ENGINE LAMP LOW ERROR

DIAGNOSTIC TROUBLE CODE (DTC) 57 (FLASH DTC=57)

CHECK ENGINE LAMP HIGH ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=6 1)

EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM CANISTER

PURGE CONTROL VALVE CIRCUIT LOW ERROR (IF APPLICABLE)

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=6 2)

EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM CANISTER

PURGE CONTROL VALVE CIRCUIT HIGH ERROR (IF APPLICABLE )

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=8 7)

A/C COMPRESSOR CLUTCH RELAY LOW ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=8 8)

A/C COMPRESSOR CLUTCH RELAY HIGH ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=9 3)

QUAD DRIVER SUB MODULE

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=5 1)

ELECTRICALLY PROGRAMMABLE READ-ONLY MEMORY(EPROM) ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=5 5)

ELECTRICALLY ERASABLE PROGRAMMABLE READ-ONLY

MEMORY (EEPROM) ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=9 1)

TACHO OUT LOW ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=9 2)

TACHO OUT HIGH ERROR

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=2 9)

FUEL PUMP RELAY SHORTED TO GROUND

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=3 2)

FUEL PUMP RELAY SHORTED TO BATTERY

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=8 3)

RECEIVED RESPONSE WAS NOT CORRECT

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=8 4)

NO RESPONSE FROM IMMOBILIZER

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=8 5)

SECURITY CODE & SE CURITY KEY NOT PROGRAMME D

DIAGNOSTIC TROUBLE CODE (DTC) (FLASH DTC=86) RECEIVED INCORRECT

SECURITY CODE

ON-VEHICLE SERV I CE PROCEDURE ECM AND SENSOR

CRANKSHAFT POSITION (CKP) SENSOR

REMOVAL

INSTALLATION

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

REMOVAL

INSTALLATION

HEATED OXYGEN SENSOR (HO2S) (IF APPLICABLE)

REMOVAL

INSPECTION

INSTALLATION

INTAKE AIR TEMPERATURE (IAT) SENSOR

REMOVAL

INSTALLATION

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

REMOVAL

INSTALLATION

MALFUNCTION INDICATOR LAMP(MIL)

ENGINE CONTROL MODULE (ECM)

ELECTROSTATIC DISCHARGE (ESD) DAMAGE

ENGINE CONTROL MODULE (ECM)

REMOVAL

INSTALLATION

POWER STEERING PRESSURE (PSP) SWITCH

REMOVAL

INSTALLATION

THROTTLE POSTION SENSOR (TPS)

REMOVAL

FUNCTION CHECK

INSTALLATION

VEHICLE SPEED SENSOR (VSS)

REMOVAL

INSPECTION

INSTALLATION

AIR INDUCTION SYSTEM

AIR FILTER

REMOVAL

INSTALLATION

IDLE AIR CONTROL (IAC) VALVE

REMOVAL

CLEANING AND INSPECTION

MEASUREMENT

INSTALLATION

INTAKE AIR DUCT

REMOVAL

INSTALLATION

KNOCK SENSOR

REMOVAL

INSTALLATION

OIL PRESSURE SWITCH

REMOVAL

INSTALLATION

FUEL METERING SYSTEM

ACCELERATOR CABLE ASSEMBLY

REMOVAL

INSPECTION

INSTALLATION

ACCELE RATOR CABLE ADJUSTMENT

ADJUSTMENT

ACCELELATOR PEDAL REPLACEMENT

REMOVAL

INSTALLATION

FUEL FILLER CAP

INSPECTION

FUEL FILTER

REMOVAL

INSPECTION

INSTALLATION

FUEL INJECTORS

REMOVAL

INSPECTION

INSTALLATION

FUEL PRESSURE REGULATOR

REMOVAL

INSTALLATION

FUEL PRESSURE RELIEF

FUEL PUMP ASSEMBLY

REMOVAL

INSPECTION

INSTALLATION

FUEL PUMP RELAY

REMOVAL

INSTALLATION

FUEL RAIL ASSEMBLY

REMOVAL

INSTALLATION

FUEL TANK

REMOVAL

INSTALLATION

THROTTLE BODY (TB)

REMOVAL

INSPECTION

INSTALLATION

ELECTRONIC IGNITION SYSYTEM

IGNITION COIL

REMOVAL

INSTALLATION

SPARK PLUGS

REMOVAL

INSPECTION

INSTALLATION

SPARK PLUG CABLES

INSPECTION

EMISSIONS

CATALYTIC CONVERTER (IF APPLICABLE)

AIR CONDITIONING RELAY

REMOVAL

INSTALLATION

IGNITION TIMING ADJUSTMENT

EVAP CANISTER HOSES (IF APPLICABLE)

EVAP CANISTER (IF APPLICABLE)

REMOVAL

INSPECTION

INSTALLATION

EVAP CANISTER PURGE VALVE SOLENOID (IF APPLICABLE)

REMOVAL

INSTALLATION

WIRING AND CONNECTORS

WIRING HARNESS SERVICE

ECM CONNECTORS AND TERMINALS

REMOVAL

INSTALLATION

CONNECTORS AND TERMINALS

WIRE HARNESS REPAIR:TWISTED SHIELDED CABLE

REMOVAL

INSTALLATION

TWISTED LEADS

REMOVAL

INSTALLATION

WEATHER-PACK CONNECTOR

TOOLS REQUIRED

REMOVAL

INSTALLATION

COM-PACK III

METRI-PACK

TOOLS REQUIRED

REMOVAL

INSTALLATION

GENERAL DE S CRIPTION

ECM AND SENSORS

58X REFE RENCE ECM INPUT

A/C REQUEST SIGNAL

CRANKSHAFT POSITION (CKP) SENSOR

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

FUEL CONTROL HEATED OXYGEN SENSOR (IF APPLICABLE)

INTAKE AIR TEMPERATURE (IAT) SENSOR

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

ENGINE CONTROL MODULE (ECM)

ECM FUNCTION

ECM COMPONENTS

ECM VOLTAGE DESCRIPTION

ECM INPUT/OUTPUTS

INPUT-OPERATING CONDITIONS READ

OUTPUTS-SYSTEMS CONTROLLED

ECM SERVICE PRECAUTIONS

THROTTLE POSITION SENSOR (TPS)

VEHICLE SPEED SENSOR (VSS)

USE OF CIRCUIT TESTING TOOLS

AFTERMARKET ELECTRICAL AND VACUUM E Q UIPMENT

ELECTROSTATIC DISCHARGE DAMAGE

AIR INDUCTION

AIR INDUCTION SYSTEM

FUEL METERING

ACCELERATION MODE

ACCELERATOR CONTROLS

BATTERY VO LTAGE CORRECTION MODE

CLEAR FLOOD MODE

DECELERATION FUEL CUTOFF (DFCO) MODE

ENGINE SPEED/VEHICLE SPEED/FUEL DISABLE MODE

FUEL CUTOFF MODE

FUEL INJECTOR

FUEL METERING SYSTEM COMPONENTS

BASIC SYSTEM OPERATION

FUEL METERING SYSTEM PURPOSE

FUEL PRESSURE REGULATOR

FUEL PUMP ELECTRICAL CIRCUIT

FUEL RAIL

IDLE AIR CONTROL (IAC) VALVE

RUN MODE (APPLICABLE TO CLOSED LOOP SYSTEMS)

STARTING MODE

THROTTLE BODY UNIT

ELECTRONIC IGNITION SYSTEM

CRANKSHAFT POSITION (CKP) SENSOR

ELECTRONIC IGNITON

IGNITION COILS

IGNITION CONTROL

IGNITION CONTROL ECM OUTPUT

ENGINE CONTROL MODULE (ECM)

SPARK PLUG

A/C CLUTCH DIAGNOSIS

A/C CLUTCH CIRCUIT OPE RATION

A/C CLUTCH CIRCUIT PURPOSE

A/C REQUEST SIGNAL

EVAPORATIVE EMISSION (EVAP) SYSTEM (IF APPLICABLE)

EVAP EMISSION CONTROL SYSTEM PURPOSE

EVAP EMISSION CONTROL SYSTEM OPERATION

SYSTEM FALUT DETECTION

POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM

CRANKCASE VENTILATION SYSTEM PURPOSE

SPECIAL SERVICE TOOLS

SPECIFICATIONS

TIGHTENING SPECIFICATIONS

APPLICATION N⋅

⋅⋅⋅m Lb Ft. Lb In.

Crankshaft Position Sensor Mounting Bolt 9 - 78

Engine Coolant Temperature Sensor 30 22 -

Fuel Pressure Regulator Attaching Screw 6.5 - 60

Fuel Rail Bolts 7 - 75

Heated Oxygen Sensor (If applicable) 5 40 -

Spark Plugs 25 18 -

Throttle Body Mounting Bolts 13 - 120

VSS Retaining Bolt 13 - 120

Intake Manifold to Cylinder Head 22 16 -

EMISSION CONTROL SYSTEM SCHEM ATICS

10 11 12 13 14 15 16

2345678

ROLL OVER&

FLOAT VALVE

FUEL PUMP

TWC CONVERTER

CRANKSHAFT

POSITION SENSOR

KNOCK SENSOR

COOLANT

TEMPERATURE

SENSOR

FUEL INJECTOR

MAP SENSOR

AIR CLEANER

HEATED

OXYGEN SENSOR

IGNITION PLUG

IAT SENSOR

THROTTLE

BODY

THROTTLE

POSITION SENSOR

IAC

VALVE

IGNITION

COIL

DUTY

SOLENOID

VALVE

CHARCOAL

CANISTER

FUEL PRESSURE

CONTROL VALVE

FUEL FILTER

FUEL PUMP

RELAY

CHECK VLV

BATTERY

+12V

IGUNITION

10A FUSE

(STOP)

DIAG

SDATA

DATA LINK

CONNECTOR

ENGINE CONTROL MODULE

METER CLUSTER

TACHO SIGNAL OUT

SPEED METER

VEHICLE SPEED SENSOR

A/C CLUTCH

A/C REQUEST

POWER STEERING SWITCH

MIL LAMP(CHECK ENGINE)

Refer to the matrix for engine specification, page 6A-11 thru 6A-17.

* If equipped.

DIAGRAMS AND SCHEMATICS

16 15 14 13 12 11 10 9

87654321

HOT AT ALL TIMES

Fuse

Stop

U/H

FUSE

BLOCK

Stop

Lamp

Engine

Control

Module

(ECM)

A1 A2 B11 E8

B/R B/L B/W O

ECM

Grounds

(Engine Block)

Diag Serial Data

HOT IN START AND RUN

Meter

Fuse

15A

I/P

FUSE

BLOCK

Malfunction

Indicator

Lamp

0.85

YEL

Vehicle

Speed Sensor

0.5

BR/Y

Instrument

Panel(I/P)

Cluster

Malfunction

Indicator

Lamp

Control

0.5

ECM

Fuse

15A

Engine

Fuse

10A

Canister

Purge

Solenoid

1.25

R/W

0.85G/W

2B/R

0.85G/R

0.85G/B

0.85G

1.25

R/W

0.85

L/Y

Fuel

Injector

Fuse

20A

Fuel

Pump

A4A6 A8 A9 A7 A5 E16

Fuel

Injector

Control

Engine

Control

Module

(ECM)

HOT WITH FUEL PUMP

RELAY ENERGIZED HOT AT ALL TIMES HOT IN RUN AND START

HOT IN START AND RUN

IG.

Coil

Fuse

15A

I/P

FUSE

BLOCK

0.85

B/O

Ignition

Coil

1.25

Engine

Control

Module

(ECM)

E1 E4 E3

Electronic Spark

Timing Control

1.25

0.5

Crankshaft

Position

Sensor

HOT WITH FUEL PUMP RELAY ENERGIZED

Sensor

10A

U/H

FUSE

BLOCK

0.85

R/G

0.5

BLK

0.5

0.5WHT

0.5RED

0.5

BLK/

RED

Engine

Control

Module

(ECM)

Sensor

Low

Sensor

High

Heated

Sensor

(D)

(C)

F12 F15

(B)

(A)

(If Applicable)

0.5 YEL

Knock

Sensor

Input

Knock

Sensor

(KS)

Engine

Control

Module

(ECM)

A/C

Compressor

Relay

Control

A16

MAG

Clutch

(Compressor)

Relay

Thermo

(1) (2)

(3) (4)

Relay:A/C

Compressor

Joint

To HA09

0.5

GR/R

B10

0.5

G/B

HOT IN START AND RUN

(2) (1)

(4) (3)

Engine

Control

Module

(ECM)

Engine

Control

Module

(ECM)

B16

0.5

L/W

0.5

L/R

Idle Air

Control

(IAC)

Valve

0.5

L/B

B15

DCBA

B13 B14

IAC

High

IAC

Low

IAC

High

IAC

Low

A B

ECM PINOUTS

ECM PINO UT TABLE, 32- PIN BLUE CONNECTOR-RO W “J1”

PIN PIN FUNCTION WIRE

COLOR IGN ON ENG RUN REFER TO

E1 Electronic Spark Timing

Coil Driver A G 12V 14V -

E2 Coil Ground A B 0V 0V -

E3 Coil Ground B B 0V 0V -

E4 Electronic Spark Timing

Coil Driver B L 12V 14V -

E5 Crank Position Sensor High G 1V 1V General Description and

Operation, Crank Position

Sensor

E6 Not Used - - - -

E7 Vss Input W 9V 11V Chassis Electrical

E8 Serial Data R 5V 5V Serial Data

E9 Not Used - - - -

E10 Not Used - - - -

E11 Not Used - - - -

E12 Not Used - - - -

E13 Not Used - - - -

E14 Not Used - - - -

E15 Not Used - - - -

E16 Ignition Feed B/Y 12V 14V General Description and

Operation

ECM PINO UT TABLE, 32- PIN BLUE CONNECTOR-RO W “J1”

PIN PIN FUNCTION WIRE

COLOR IGN ON ENG RUN REFER TO

F1 Crankshaft Position Sensor

Low R 1V 1V General Description and

Operation, Crankshaft

Position Sensor

F2 Not Used - - - -

F3 Not Used - - - -

F4 Not Used - - - -

F5 Not Used - - - -

F6 Knock Sensor Input Y 0V 0V General Description and

Operation, Knock Sensor

F7 Not Used - - - -

F8 Not Used - - - -

F9 Not Used - - - -

F10 Intake Air Temperature

Sensor Y/G 2V 2V General Description and

Operation, IAT

F11 Not Used - - - -

F12 Heated O2 Sensor Low

(If applicable) - - - General Description and

Operation, Heated O2

Sensor

F13 Not Used - - - -

F14 Engine Coolant

Temperature L/R 2V

(0V=151°C) 3V

(5V=-40°C) General Description and

Operation, Engine Coolant

Temperature Sensor

F15 Heated O2 Sensor

(If applicable) L 1.0V 0V General Description and

Operation, Heated O2

Sensor

F16 Power Steering Pressure

Switch Input G/Y 12V 14V General Description and

Operation, PSP

ECM PINO UT TABLE, 32- PIN RED CONNECTOR-RO W “J2”

PIN PIN FUNCTION WIRE

COLOR IGN ON ENG RUN REFER TO

A1 Power Ground A B/R 0.0V 0V Appropriate Sensor

A2 Sensor Ground B B/L 0.0V 0V Appropriate Sensor

A3 5 Volt Reference Signal R 5.0V 5V Appropriate Sensor

A4 Battery Feed R/W 12V 14V Chassis Electrical

A5 Battery R/W 12V 14V Chassis Electrical

A6 Injector #4 Cyl G 0V 14V General Description and

Operation, Fuel Injector

A7 Injector #1 Cyl G/W 0V 14V General Description and

Operation, Fuel Injector

A8 Injector #3 Cyl G/B 0V 14V General Description and

Operation, Fuel Injector

A9 Inject #2 Cyl G/R 0V 14V General Description and

Operation, Fuel Injector

A10 Not Used - - - -

A11 Not Used - - - -

A12 Not Used - - - -

A13 Fuel Pump Relay G/W 12V 0V On-Vehicle Service Fuel

Pump Relay

A14 Charcoal Canister Purge

Solenoid Valve

(If applicable)

R/L 12V 14V -

A15 Not Used - - - -

A16 A/C Clutch W/R 0V 0V -

ECM PINO UT TABLE, 32- PIN RED CONNECTOR-RO W “J2”

PIN PIN FUNCTION WIRE

CLOLR IGN ON ENG RUN RDFER TO

B1 TPS

5 Volt Reference Signal A G 0V 0V Appropriate Sensor

B2 TPS

5 Volt Reference Signal B G 0V 0V Appropriate Sensor

B3 Not Used - - - -

B4 Check Engine Lamp R/Y 0V 14V Chassis Electrical

B5 Tacho-meter Signal B/R 12V 8-10V General Description and

Operation

B6 Not Used - - - -

B7 Map Input W 5.0V

(0V=10kpa) 1.0V

(5V=104kpa) General Description and

Operation, Manifold Absolute

Sensor

B8 Throttle Position Sensor B 1.0V 1.0V General Description and

Operation, TPS

B9 Not Used - - - -

B10 A/C Request Signal G/B 0V 0V -

B11 DLC (Digital Input) B/W 12V 14V Diagnosis, Serial Data

B12 Not Used - - - -

B13 IAC ”B” High L/R 1V 1V General Description and

Operation, IAC

B14 IAC ”B” Low L/B 11V 13V General Description and

Operation, IAC

B15 IAC ”A” Low L/W 1V 1V General Description and

Operation, IAC

B16 IAC ”A” High L 11V 13V General Description and

Operation, IAC

COMP ONENT LOCATOR

HO2S(if applicable) THREE-WAY CATALYTIC CONVERTER

(if applicable)

VEHICLE

SPEED SENSOR

(VSS)

FUEL FILTER

THROTTLE POSITION SENSOR

MAP SENSOR

EVAP PURGE CONTROL

SOLENOID VALVE

FUEL INJECTOR

IGNITION COIL

KNOCK SENSOR

CRANKSHAFT POSITION SENSOR

HEATED

OXGEN

SENSOR

(if applicable)

THROTTLE BODY

IAC VALVE

AIR CLEANER

INTAKE AIR

TEMPERATURE

SENSOR

ENGINE CO MPONENT LOCATO R TABLE

NUMBER NAME LOCATION

1 Engine Coolant Temperature (ECT) Sensor Front of engine, next to the thermostat housing

2Heated Oxygen Sensor (HO2S) On the exhaust pipe, left side of engine,

immediately behind the exhaust manifold

3 Air Cleaner Left front the engine bay

4 Intake Air Temperature (IAT) Sensor On the intake air duct near the air cleaner

5 Positive Crankcase Ventilation (PCV) Port On the right front corner of the valve cover

6 Fuel Pressure Regulator On the rear end of the fuel rail

7 Throttle Body Between the intake air duct and the intake

manifold

8 Fuse/Relay Box Along the inside of the right fender

9 Throttle Position (TP) Sensor On the front of the throttle body

10 Idle Air Control (IAC) Valve Under the TP sensor

11 EVAP Canister Purge Control Solenoid On the intake manifold

12 Ignition Coil Above the starter motor

13 Manifold Absolute Pressure (MAP) Sensor Bolted to the front edge of the intake

manifold, under the fuel rail

*14 EVAP Canister On the left side Tire house

*15 Check and Relief valve On the canister hold brace

* If applicable

UNDERCARRI AGE COMPONENT LOCATOR TABLE

NAME LOCATION

Fuel Pump Assembly Installed in the top of the fuel tank

EVAP Purge Control Solenoid Valve At the right rear of the engine

Vehicle Speed Sensor (VSS) Protrudes from the right side of the transmission

housing, rear the output shaft

Crankshaft Position (CKP) Sensor Lower left hand front of engine, behind power steering

pump bracket

UNDERHOOD ( U/H) FUSE AND RELAY PANEL

INSTRUMENT PANEL (I/P) FUSE BLO CK

DIAGNOSIS

STRATEGY-BASED DIAGNO STICS

The strategy-based diagnostic is a uniform approach

to repair all Electrical/Electronic (E/E) systems. The

diagnostic flow can always be used to resolve an E/E

system problem and is a starting point when repairs

are necessary. The following steps will instruct the

technician how to proceed with a diagnosis:

1. Verify the customer complaint.

•To verify the customer complaint, the technician

should know the normal operation of the system.

2. Perform preliminary checks.

•Conduct a thorough visual inspection.

•Review the service history.

•Detect unusual sounds or odors.

•Gather diagnostic trouble code information to

achieve an effective repair.

3. Check bulletins and other service information.

•This includes videos, newsletters, etc.

4. Refer to service info (manual) system check(s).

•“System checks” contain information on a

system that may not be supported by one or

more DTCs. System checks verify proper

operation of the system. This will lead the

technician in an organized approach to

diagnostics.

5. Refer to service diagnostics.

DTC STORED

Follow the designated DTC chart exactly to make an

effective repair.

NO DTC

Select the symptom from the symptom tables. Follow

the diagnostic paths or suggestions to complete the

repair. You may refer to the applicable

component/system check in the system checks.

NO MATCHING SYM PTOM

1. Analyze the complaint.

2. Develop a plat for diagnostics.

3. Utilize the wiring diagrams and the theory of

operation.

Call technical assistance for similar cases where

repair history may be available. Combine technician

knowledge with efficient use of the available service

information.

INTERMITTENTS

Conditions that are not always present are called

intermittents. To resolve intermittents, perform the

following steps:

1. Observe DTCs and DTC modes

2. Evaluate the symptoms and the conditions

described by the customer.

3. Use a check sheet or other method to identify the

circuit or electrical system component.

4. Follow the suggestions for intermittent diagnosis

found in the service documentation.

Most Scan T ools, suc h as the Tech 2 and the 5-8840-

2392-0, have data-capturing capabilities that can

assist in detecting intermittents.

NO TROUBLE FOUND

This condition exists when the vehicle is found to

operate normally. The condition described by the

customer may be normal. Verify the customer

complaint against another vehicle that is operating

norm ally. T he condition may be intermittent. Verif y the

complaint under the conditions described by the

customer before releasing the vehicle.

1. Re-examine the complaint.

When the complaint cannot be successfully found

or isolated, a re-evaluation is necessary. The

complaint should be re-verified and could be

intermittent as defined in Intermittents, or could be

normal.

2. Repair and verify.

After isolating the cause, the repairs should be

made. Validate for proper operation and verify that

the symptom has been c orrec ted. T his m ay involve

road testing or other methods to verify that the

complaint has been resolved under the following

conditions:

•Conditions noted by the customer.

•If a DTC was diagnosed, verify a repair by

duplicating conditions present when the DTC

was set as noted in the customer complaint.

VERIFYING VEHICLE REPAIR

Verification of the vehicle repair will be more

comprehensive for vehicles with OBD system

diagnostics. Following a repair, the technician should

perform the following steps:

IMPORTANT: Follow the steps below when you verif y

repairs on O BD system s. Failure to f ollow these steps

could result in unnecessary repairs.

1. Review and record the customer complaint for the

DTC which has been diagnosed.

2. Clear the DTC(s).

3. Operate the vehicle within conditions noted in the

customer complaint.

4. Monitor the DTC status information for the specific

DTC which has been diagnosed until the diagnos tic

test associated with that DTC runs.

GENERAL SERVICE INFORMATION

OBD SERVICEABILITY ISSUES

FUEL QUALITY

Fuel quality is not a new issue for the automotive

industry. The Reed Vapor Pressure of the fuel can

also create problems in the fuel system, especially

during the spring and fall months when severe

ambient temperature swings occur. A high Reed

Vapor Pressure could show up as a rich DTC due to

excessive canister loading. High vapor pressures

generated in the fuel tank can also affect the

Evaporative Emission diagnostic as well.

Using fuel with the wrong octane rating for your

vehicle may cause driveability problems. Many of the

major fuel companies advertise that using “premium”

gasoline will improve the performance of your vehicle.

Most premium fuels use alcohol to increase the

octane rating of the fuel. Although alcohol-enhanced

fuels may raise the octane rating, the fuel's ability to

turn into vapor in cold tem peratures deteriorates. This

may affect the starting ability and cold driveability of

the engine.

Low fuel levels can lead to fuel star vation, lean engine

operation, and eventually engine misfire.

NON-O E M PARTS

All of the OBD diagnos tics have been c alibrated to run

with OEM parts. Small leaks in the exhaust system

near the heated oxygen sensor can also cause the

MIL (“Check Engine“ lamp) to turn on.

Aftermarket electronics, such as cellular phones,

stereos, and anti-theft devices, may radiate EMI into

the control s ystem if they are improper ly installed. T his

may cause a f alse sens or reading and turn on the MIL

(“Check Engine” lamp).

POOR VEHICLE MAINTENANCE

The sensitivity of OBD diagnostics will cause the MIL

(“Check Engine” lam p) to turn ON if the vehicle is not

maintained properly. Restricted air filters, fuel filters,

and crankcase deposits due to lack of oil changes or

improper oil viscosity can trigger actual vehicle faults.

Poor vehicle maintenance can not be classified as a

“non-vehicle fault” , but with the sensitivity of OBD

diagnostics, vehicle maintenance schedules must be

more closely followed.

RELATED SYSTEM FAULTS

Many of the OBD system diagnostic s will not run if the

ECM detects a fault on a related system or

component. One example would be that if the ECM

detected a Evap. Purge Solenoid fault, The diagnosis

on the Oxygen Sensor (If applicable) would be

suspended until the Evap. Purge Solenoid repaired. If

this happened, the customer may have to make two

trips to the dealership in order to repair the vehicle.

MAINTENANCE SCHEDULE

Refer to the Maintenance Schedule.

VISUAL /PHYSICAL ENGINE

CO MPARTMENT INSPECTION

Perform a careful visual and physical engine

compartment inspection when performing any

diagnostic procedure or diagnosing the cause of an

emis sion test failure. T his can of ten lead to repairing a

problem without further steps. Use the following

guidelines when performing a visual/thysical

inspection:

•Inspect all vacuum hoses for punches, cuts,

disconnects, and correct routing.

•Inspect hoses that are difficult to see behind other

components.

•Inspect all wires in the engine compartment for

proper connections, burned or chafed spots,

pinched wires, contact with sharp edges or contact

with hot exhaust manifolds or pipes.

BASIC KNOWLEDGE OF TOOLS

REQUIRED

Notice: Lack of basic knowledge of this powertrain

when perform ing diagnostic pr ocedures c ould result in

an incorrect diagnosis or damage to powertrain

components. Do not attempt to diagnose a powertrain

problem without this basic knowledge.

A basic understanding of hand tools is necessary to

effectively use this section of the Service Manual.

SERIAL DATA CO MMUNICATIONS

This vehicle utilizes the serial data communication

system. Each bit of information can have one of two

lengths: long or short. This allows vehicle wiring to be

reduced by transmitting and receiving multiple signals

over a single wire. The messages carried on serial

data streams are also prioritized. If two messages

attempt to establish communications on the data line

at the same time, only the message with higher prior ity

will continue. The device with the lower priority

message must wait. For more information on this

system of coding. On this vehicle the Scan

Tool displays the actual values for vehicle parameters.

It will not be necessary to perform any conversions

from coded values to actual values.

ON-BOARD DIAGNOSTIC (OBD)

ON-BO ARD DIAGNOSTIC TESTS

Miscellaneous Test:

A miscellaneous test is a kind of the On-Board

Diagnostics.

Using a tech 2, the miscellaneous test can be

conducted, followings are brief description about the

miscellaneous tests.

To perform the miscellaneous test, allows the

displayed menu on the tech 2. Sub-menu of

miscellaneous test are as follows.

•Check powertrain lamp:

This test allows to turn on and off the powertrain

warning lamp in the instrument cluster.

•Fuel Pump:

Fuel pump test allows to turn on and off the fuel

pump.

If turned off while the engine is running, the engine

will stall.

•A/C Clutch:

The A/C Clutch test allows to turn on and off the

airconditioning.

•Canister Purge Control Solenoid Valve:

This function takes control of the canister purge

control solenoid valve.

The on command represents a 100% pwm, the off

command a 0% pwm.

•IAC (Idle Air Control) System:

•RPM control

This function allows the user to slew the desired

RPM via increments of 25 RPM with a minimum

of 600 RPM and a maximum of 2000 RPM.

The start value will be at 1150 RPM.

•IAC Control

This function allows the user to slew the IAC via

increments of 25 steps with a minim um of 0 s teps

and a maximum of 250 steps.

The start value will be at idle steps.

•IAC Reset

The user will have the ability to perform an IAC

reset.

Each keypress will actuate the command to reset.

•Fuel Trim Reset:

This function allows the user to command the ECM

to perform an Long Term Fuel Trim reset, also

known as a Block Learn Memory reset.

Each keypress will actuate the command to reset.

•Fueling Mode:

This function provides the user with the ability to

enable or disable closed loop fuel control.

•Air Fuel Ratio:

This function allows the user to slew the control

state of the A/F ratio within a minimum of 11.7:1

and a maximum of 17.7:1.

The test starts at an A/F ratio of 14.7 : 1.

The incremental control is 0.5 steps per keypress.

COMPREHENSIVE COMP ONENT

MO NITOR DIAGNOSTIC

OPERATION

Comprehensive component monitoring diagnostics

are involved to monitor emissions-related input and

output engine components.

INPUT COMPONENTS

Input components are monitored for circuit continuity

and out-of-range values. This includes rationality

checking. Rationality checking refers to indicating a

fault when the signal from a sensor does not seem

reasonable, i.e. Throttle Position (TP) sensor that

indicates high throttle position at low engine loads or

MAP voltage). Input com ponents may include, but are

not limited to the following sensors:

•Vehicle Speed Sensor (VSS)

•Crankshaft Position (CKP) sensor

•Throttle Position (TP) sensor

•Engine Coolant Temperature (ECT) sensor

•Intake Air Temperature Sensor (IAT)

•Manifold Absolute Pressure (MAP) sensor

In addition to the circuit c ontinuity and rationality c hec k

the ECT sensor is m onitored for its ability to ac hieve a

steady s tate tem perature to enable “Clos ed Loop” fuel

control (If applicable).

OUTPUT CO MPONENTS

Output components are diagnosed for proper

response to control module commands. Components

where functional monitoring is not feasible will be

monitor ed f or c irc uit continuity and out-of-r ange values

if applicable.

Output components to be monitored include, but are

not limited to the following circuit:

•Idle Air Control (IAC) Motor

•EVAP Canister Purge Valve Solenoid

•A/C relays

•VSS output

•MIL control

Refer to ECM and Sensors in General Descriptions.

PASSI VE AND ACTIVE DIAGNOSTIC TESTS

A passive test is a diagnostic test which simply

monitors a vehicle system or component. Conversely,

an active test, actually tak es s ome sor t of action when

perfor m ing diagnostic functions , often in res ponse to a

failed passive test.

INTRUSIVE DIAGNOSTIC TESTS

This is any on-board test run by the Diagnostic

Management System which may have an effect on

vehicle performance or emission levels.

WARM -UP CYCLE

A warm-up cycle means that engine at temperature

must reach a minimum of 70°C(160°F) and rise at

least 22°C(40°F) over the course of a trip.

COMMON OBD TERMS

DIAGNOSTIC FOR CLOSED LOOP SYSTEM

When used as a noun, the word diagnostic refers to

any on-board test run by the vehicle's Diagnostic

Management System . A diagnostic is sim ply a test run

on a system or component to determine if the system

or component is operating according to specification.

FOR CLOSED LO OP SYSTEM

There are many diagnostics, shown in the following

list:

•Oxygen sensors

•Oxygen sensor heaters

ENABLE CRITERI A

The term “enable criteria” is engineering language for

the conditions necessary for a given diagnostic test to

run. Each diagnostic has a specific list of conditions

which must be met before the diagnostic will run.

“Enable criteria” is another way of saying “conditions

required” .

The enable criteria for each diagnostic is listed on the

first page of the DTC description under the heading

“Conditions for Setting the DTC” . Enable criteria

varies with each diagnostic, and typically includes, but

is not limited to the following items:

•engine speed

•vehicle speed

•ECT

•MAP

•IAT

•TP

•high canister purge (If applicable)

•A/C ON

TRIP

Technically, a trip is a key on-run-key off cycle in

which all the enable criteria for a given diagnostic are

met, allowing the diagnostic to run. Unfortunately, this

concept is not quite that simple. A trip is official when

all the enable criteria for a given diagnostic are met.

But because the enable criteria vary from one

diagnostic to another, the definition of trip varies as

well. Some diagnostics are run when the vehicle is at

operating temperature, some when the vehicle first

start up; som e requir e that the vehicle be c ruising at a

steady highway speed, some run only when the

vehicle is at idle. Som e run only im mediately following

a cold engine start-up.

A trip then, is defined as a key on-run-key off cycle in

which the vehicle was operated in such a way as to

satisfy the enabled criteria for a given diagnostic, and

this diagnostic will consider this cycle to be one trip.

However, another diagnostic with a different set of

enable criteria (which were not m et) during this driving

event, would not consider it a trip. No tr ip will occ ur f or

that particular diagnostic until the vehicle is driven in

such a way as to meet al the enable criteria

THE DIAGNOSTIC EXECUTIVE

The Diagnostic Executive is a unique segment of

software which is des igned to coordinate and prioritize

the diagnostic procedures as well as define the

protocol f or recording and displaying their r esults. T he

main responsibilities of the Diagnostic Executive are

listed as follows:

•Commanding the MIL(“Check Engine” lamp) ON

and OFF

•DTC logging and clearing

•Current status information ON each diagnostic

The Diagnos tic Exec utive records DT Cs and tur ns ON

the MIL when em is sion- related f aults oc c ur. It c an als o

turn OFF the MIL if the conditions c ease which c aus ed

the DTC to set.

DIAGNOSTIC INFORMATION

The diagnostic charts and functional checks are

designed to locate a faulty circuit or component

through a process of logical decisions. The charts are

prepared with the requirement that the vehicle

functioned correctly at the time of assembly and that

there are not multiple faults present.

Ther e is a continuous self -diagnosis on certain control

functions. This diagnostic capability is complimented

by the diagnos tic proc edur es contained in this manual.

The language of communicating the source of the

malfunction is a system of diagnostic trouble codes.

When a malf unc tion is detec ted by the control m odule,

a diagnostic trouble code is set and the Malfunction

Indicator Lamp (MIL)(“Check Engine” lamp) is

illuminated.

MALFUNCTION INDICATOR LAMP (MI L)

The Malfunction Indicator Lamp (MIL) looks the same

as the MIL you are already familiar with (“Check

Engine” lamp).

Basically, the MIL is turned ON when the ECM detects

a DTC.

EXTINGUISHING THE MIL

The MIL (“Check Engine” lamp) is on the instrument

panel and has the following functions:

•It informs the driver that a fault that affects vehicle

emission levels has occurred and that the vehicle

should be taken for service as soon as possible.

•As a bulb and system check, the MIL will come on

with the key on and the engine not running. When

the engine is started, the MIL will turn OFF.

•When the MIL remains on while the engine is

running, or when a malfunction is suspected due to

a driveability or emissions problem, a Powertrain

On-Board Diagnostic (OBD) System Check must be

performed. The procedures for these checks are

given in On-Board Diagnostic (OBD) System

Check. These checks will expose faults which may

not be detected if other diagnostics are performed

first.

Once the ECM determines that a fault(s) has been

rectified then the MIL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

Refer to clearing Diagnostic Trouble Code

DATA LINK CONNECTOR (DLC)

The Provision for communicating with the control

module is the Data Link Connector ( DLC). It is located

at the lower left of the instrum ent panel behind a s m all

square cover. The DLC is used to connect to a Scan

Tool. Some comm on uses of the Scan Tool are listed

below:

•Identifying stored Diagnostic Trouble Codes (DTCs)

•Clearing DTCs

•Performing output control tests

•Reading serial data

READING FLASH DIAGNOSTIC TROUBLE

CODES

The provision for communicating with the Engine

Control Module (ECM) is the Data Link Connector

(DLC). The DLC is located behind the lower front

instrument panel. It is used in the assembly plant to

receive information in checking that the engine is

operating properly before it leaves the plant.

The diagnostic trouble code(s) (DTCs) stored in the

ECM’s memory can be read either through a hand-

held diagnostic scanner plugged into the DLC or by

counting the number of f lashes of the ”Check Engine”

Malfunction lndicator Lamp (MIL) when the diagnostic

test terminal of the DLC is grounded. The DLC

terminal ”6” (diagnostic request) is pulled ”Low”

(grounded) by jumpering to DLC ter m inal ”5”, Whic h is

a ground wire.

This will signal the ECM that you want to ”flash”

DTC(s ), if any are pr esent. Once term inals ”5” and ”6”

have been connected, the ignition switch must be

moved to the ”ON” position, with the engine not

running. At this point, the ”Check Engine” MIL should

flash DTC12 three times consecutively.

This would be the following flash, sequence: ”flash,

pause, flash-flash, long pause, flash, pause, flash-

flash, long pause, flash, pause, flash-flash”. DTC12

indicates that the ECM’s diagnostic system is

operating. If DTC12 is not indicated, a problem is

present within the diagnostic system itself, and should

be addressed by consulting the appropriate diagnos tic

chart in DRIVEABILITY AND EMISSIONS.

Following the output of DTC12, the ”Check Engine”

MIL will indicate a DTC three times if a DTC is

present, or it will simply continue to output DTC12. If

more than one DTC three has been stored in the

ECM’s memory, the DTC(s) will be output from the

lowest to the highest, with each DTC being displayed

three times.

READING DIAGNOSTIC TROUBLE CODES

USING A TECH 2

The procedure for reading diagnostic trouble code(s)

is to used a diagnostic Tech 2. When r eading DTC(s ),

follow instructions supplied by Tech 2 manufacturer.

CLEARI NG DIAGNOSTIC TROUBLE CODES

IMPORTANT: Do not clear DTCs unless directed to

do so by the service information provided for each

diagnostic procedure.

If the fault that caused the DTC to be stored into

mem ory has been correc ted, the Diagnostic Executive

will begin to count the ”warm -up” c ycles with no further

faults detected, the DTC will automatically be cleared

from the ECM memory.

To clear Diagnostic Trouble Codes (DTCs), use the

Tech 2 ”clear DTCs” or ”clear information” function.

When clearing DTCs follow instructions supplied by

the Tech 2 manufacturer.

When a Tech 2 is not available, DTCs can also be

cleared by disconnecting one of the following sources

for at least thirty (30) seconds.

NOTE: To prevent system damage, the ignition key

must be ”OFF” when disconnecting or reconnecting

battery power.

•The power sour ce to the contr ol m odule. Exam ples :

fuse, pigtail at battery ECM connectors etc.

•The negative battery cable. (Disconnecting the

negative battery cable will result in the loss of other

on-board memory data, such as preset radio

tuning).

ON-BO ARD DIAGNO SIS (SELF-DIAG NOSIS)

1. The Engine Control Module (ECM) conducts a self-

test of most of the wiring and components in the

system each tim e the key is turned to ON, and can

detect faults in the system while the key is ON. If a

fault is detected, the ECM will store a trouble code

in mem ory and flash the CHECK ENGINE indicator

to alert the driver.

2. The Diagnostic Trouble Codes (DTC) can be

displayed by shorting together terminals and of the

Data Link Connector (DLC) located behind front

console.

The CHECK ENGINE indicator will flash DTC 12

three times, followed by any DTC. If several DTC

are stored, each DTC will be displayed three times.

The DTC will be displayed in numerical order. The

DTC display will continue as long as the DLC is

shorted.

Some DT C can cause other DTC to be stored, It is

important to diagnose and repair the lowest

numbered DTC first before going on to the higher

numbered DTC.

TECH 2 SCAN TOOL

From 98 MY, Isuzu dealer service departments are

recommended to use Tech 2. Please refer to Tech 2

user guide.

LEGEND

(1) PCMCIA Card

(2) RS 232 Loop Back Connector (3) SAE 16/19 Adaptor

(4) DLC Cable

(5) Tech-2

GE TTING STARTED

•Before operating the Isuzu PCMCIA card with the

Tech 2, the following steps must be performed:

1. The Is uzu 98 System PCMCIA c ard (1) inserts into

the Tech 2 (5)

2. Connect the SAE 16/19 adapter (3) to the DLC

cable (4).

3. Connect the DLC cable to the Tech 2 (5)

4. Make sure the vehicle ignition is off.

5. Connect the Tech 2 SAE 16/19 adapter to the

vehicle DLC.

6. The vehicle ignition turns on.

7. Verify the Tech 2 power up display.

NOTE: The RS232 Loop back connector is only to use

for diagnosis of Tech 2 and refer to user guide of the

Tech 2.

OPERATING PROCEDURE

The power up sc reen is displayed when you power up

the tester with the Isuzu systems PCMCIA card.

Follow the operating procedure below.

•The following table shows, the Tech 2 menu

structure.

F0: Diagnostic Trouble Codes

F0: Read DTC Info Ordered By Priority

F1: Clear DTC Information

F1: Data Display

F0: Engine Data

F2: O2 Sensor Data

F2: Snapshot

F3: Miscellaneous Tests

F0: Engine Check Light

F1: Relays

F1: A/C Relay

F2: Fuel Pump Relay

*F3: Low Fan Replay

*F4: High Fan Replay

F2: Canister Purge Solenoid

F3: IAC System

F1: RPM Control

F2: IAC Control

F3: IAC Reset

F4: Fuel System

F1: Fuel Trim Reset

F2: Fueling Mode

F7: Air Fuel Ratio

Note : *F3 & F4 not applicable to TF models

Note: Selection Table

Appricable

Version Engine

Displacement Compression

Ratio Fuel Octane No.

(RON)

Destination

*Shows w/canister for EVAP. Emission

control

Version 1 2.2L 8.6 80 Leaded/Un-

Leaded

*Ecuador, *Gulf, China, Egypt, Kenya,

Nigeria and Philippine

Version 2 2.2L 9.2 85 Leaded/Un-

Leaded Chile, Colombia, Guatemala and Costarica

Version 3 2.2L 9.2 91 Un-Leaded *Australia, *New Zealand and South Africa

Version 4 2.0L 8.8 91 Leaded/Un-

Leaded South Africa

VERIFYING VEHICLE REPAIR

Verification of vehicle repair will be more

comprehensive for vehicles with OBD system

diagnostics. Following a repair, the technician should

perform the following steps:

1. Review and record the customer complaint for the

DTC which has been diagnosed.

2. Clear DTC(s).

3. Operate the vehicle within conditions noted in the

customer complaint.

4. Monitor the DTC status information for the specific

DTC which has been diagnosed until the diagnos tic

test associated with that DTC runs.

Following these steps are very important in verifying

repairs on OBD systems. Failure to follow these steps

could result in unnecessary repairs.

READING DI AGNOSTIC TROUBLE

CODES USING A SCAN TOOL

The procedure for reading diagnostic trouble code(s)

is to use a diagnostic Scan Tool. When reading

DTC(s), follow instructions supplied by tool

manufacturer.

CLEARI NG DIAGNOSTIC TROUBLE CODES

IMPORTANT: Do not clear DTCs unless directed to

do so by the service information provided for each

diagnostic procedure.

If the fault that caused the DTC to be stored into

mem ory has been correc ted, the Diagnostic Executive

will begin to count the “warm -up” c ycles with no further

faults detected, the DTC will automatically be cleared

form the ECM memory.

To clear Diagnostic Trouble Codes (DTCs), use the

diagnostic Scan Tool “clear DTCs” or “clear

information” function. When clearing DTCs follow

instructions supplied by the tool manufacturer.

W hen a Scan T ool is not available, DT Cs can als o be

cleared by disconnecting one of the following sources

for at least thirty (30) seconds.

Notice: To prevent system damage, the ignition key

must be OFF when disconnecting or reconnecting

battery power.

•The power sour ce to the contr ol m odule. Exam ples :

fuse, pigtail at battery ECM connectors etc.

•The negative battery cable. (Disconnecting the

negative battery cable will result in the loss of other

on-board memory data, such as preset radio

tuning).

DTC MODES

There are 2 options available in the Scan Tool DTC

mode to display the enhanced information available.

After selecting DTC, the following menu appears:

•DTC Info

•Clear DTC Info

The following is a brief description of each of the sub

menus in DTC Info and Specific DTC. The order in

which they appear here is alphabetical and not

necessarily the way they will appear on the Scan Tool.

DTC INFORMATION MODE

Use the DTC info mode to search for a stored DTC

Refer to “Diagnostic Trouble Codes” list.

CLEAR DTC INFORMATIO N

The command for clearing DTC’s performs a

complete reset of the ECM.

PRIMARY SYSTEM-BASED

DIAGNOSTICS

There are primary system-based diagnostics which

evaluate system operation and its effect on vehicle

emissions. T he primary system-based diagnostics are

listed below with a brief description of the diagnostic

function:

FUEL CONTROL HEATED OXYGEN

SENSORS (IF APPLICABLE)

The main function of the fuel control heated oxygen

sensors is to provide the control module with exhaust

stream oxygen content information to allow proper

fueling and maintain emissions within mandated

levels. After it reaches operating temperature, the

sensor will generate a voltage, inversely proportional

to the amount of oxygen present in the exhaus t gas es.

The control module uses the signal voltage from the

fuel control heated oxygen sensors while in “Closed

Loop” to adjust fuel injector pulse width. While in

“Closed Loop” , the ECM can adjust fuel delivery to

maintain an air/fuel ratio which allows the best

combination of emission control and driveability. The

fuel control heated oxygen sensors are also used to

determine catalyst efficiency.

HO2S HEATER

Heated oxygen sensors are used to minimize the

amount of time requir ed for “Closed Loop” fuel contr ol

to begin operation and to allow accurate catalyst

monitoring. The oxygen sensor heater greatly

decreases the amount of tim e required for fuel control

sensor (HO2S) to become active.

ON-BO ARD DIAGNOSTIC (OBD) SYSTEM CHECK

16 15 14 13 12 11 10 9

87654321

HOT AT ALL TIMES

Fuse

Stop

10A

U/H

FUSE

BLOCK

Stop

Lamp

Engine

Control

Module

(ECM)

0.5G

A1 B11 E8

B/R 0.5

0.5

ECM

Grounds

(Engine Block)

Diag Serial Data

1.25

CIRCUIT DESCRIPTION

The on-board diagnostic system check is the starting

point for any driveability complaint diagnosis. Before

using this procedure, perform a careful visual/physical

check of the ECM and engine grounds for cleanliness

and tightness.

The on-board diagnostic system check is an organized

approach to identifying a problem created by an

electronic engine control system malfunction.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection,

rubbed-through wire insulation or a wire broken inside

the insulation. Check for poor connections or a

damaged harness. Inspect the ECM harness and

connectors for improper mating, broken locks,

improperly formed or damaged terminals, poor

terminal-to-wire connection, and damaged harness.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart:

1. The MIL (“Check Engine” lamp) should be ON

steady with the ignition ON/engine OFF. If not,

isolate the malfunction in the MIL circuit.

2. Checks the serial data circuit and ensures that the

ECM is able to transmit serial data.

3. This test ensures that the ECM is capable of

controlling the MIL and the MIL driver circuit is not

shorted to ground.

4. If the engine will not start, the Cranks But Will Not

Run chart should be used to diagnose the

condition.

7. A Scan Tool parameter which is not within the

typical range may help to isolate the area which is

causing the problem.

ON-BO ARD DIAGNOSTIC (OBD) SYSTEM CHECK

STEP ACTION VALUE(S) YES NO

1. Ignition ON engine OFF.

2. Observe the malfunction indicator lamp (MIL or

“Check Engine” lamp).

Is the MIL (“Check Engine” lamp) ON?

Go to Step 2

Go to

No MIL

1. Ignition OFF.

2. Install a Scan Tool.

3. Ignition ON.

4. Attempt to display ECM engine data w ith the Scan Tool.

Does the Scan Tool display ECM data?

Go to Step 3

Go to Step 8

1. Using the Scan Tool output tests function, select MIL dash

lamp control and command the MIL OFF.

2. Observe the MIL.

Did the MIL turn OFF?

Go to Step 4

Go to

MIL(“Check

Engine” Lamp)

On Steady

4Attempt to start the engine.

Did the engine start and continue to run? - Go to Step 5

Go to

Cranks But

Will Not Run

5Select “Display DTCs” with the Scan Tool.

Are any DTCs stored? -Go to Step 6 Go to Step 7

Are two or more of the following DTCs stored?

•14

•21

•22

•33

•34

•69

Go to

“Multiple

ECM

Information

Sensor

DTCs

Set”

Go to

applicable

DTC table

Compare ECM data values displayed on the Scan Tool to the

typical engine scan data values.

Are the displayed values normal or close to the typical values? -

Go to Step 8

Refer to

indicated

Component

System Checks

STEP ACTION VALUE(S) YES NO

1. Ignition OFF, disconnect the ECM.

2. Ignition ON, engine OFF.

3. Check the serial data circuit for an open, short to ground, or

short to voltage. Also, check the DLC ignition feed circuit for an

open or short to ground and the DLC ground circuits for an

open.

4. If a problem is found, repair as necessary. Was a problem

found?

Go to Step 2 Go to Step 9

1. Refer to Engine Control Module (ECM) in On-Vehicle Service.

2. Attempt to display ECM data with the Scan Tool.

Does the Scan Tool display ECM engine data? -

Go to Step 2 Go to Step 10

10 Replace the EPROM or ECM. Note) Refer to 6E1-243 - Verify Repair -

A/ C CLUTCH CONTROL CI RCUIT DIAGNOSIS

CIRCUIT DESCRIPTION

When air conditioning and blower fan are selected,

and if the system has a suf ficient refrigerant charge, a

12-volt signal is supplied to the A/C request input of

the engine control module (ECM). The A/C request

signal may be temporarily canceled during system

operation by the electronic thermostat in the

evaporator case. The electronic thermostat may

intermittently remove the control circuit ground for the

A/C thermostat relay to prevent the evaporator from

forming ice. W hen the A/C request signal is received

by the ECM, the ECM supplies a ground from the

compressor clutch relay if the engine operating

conditions are within acceptable ranges. W ith the A/C

compressor relay energized, battery voltage is

supplied to the compressor clutch coil.

The ECM will enable the c om press or clutch to engage

whenever A/C has been selected with the engine

running, unless any of the following conditions are

present:

•The throttle is greater than 95%.

•The engine speed is greater than 6000 RPM.

•The engine coolant temperature (ECT) is greater

than 122°C(252°F).

•Fan switch is OFF.

•A/C reguest switch is OFF.

• Thermo switch (FRT) is OFF.

• Pressure switch is OFF.

• Ignition switch is OFF.

DIAGNOSTIC AIDS

To diagnose an intermittent fault, check for the

following conditions:

• Poor connection at the ECM-Inspect harness

connections for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness-Inspect the wiring harness for

damage; shorts to Ground, shorts to Battery

Voltage, and Open circuits. If the harness appears

to be OK, observe the A/C clutch while moving

connectors and wiring harnesses related to the A/C.

A sudden clutch malfunction will indicate the source

of the intermittent fault.

A/C CLUTCH DIAGNOSIS

This chart should be used for diagnosing the electrical

portion of the A/C compressor clutch circuit. A Scan

Tool will be used in diagnosing the system. The Scan

Tool has the ability to read the A/C request input to the

ECM. The Scan Tool can display when the ECM has

commanded the A/C clutch ON. The Scan Tool should

have the ability to override the A/C request signal and

energize the A/C compressor relay.

A/C CLUTCH CONTROL CIRCUIT DIAGNOSIS

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System Check”

performed? - Go to Step 2 Go to OBD

System Check

1. Ignition ON, Engine OFF.

2. Review and record the customer complaint.

3. Operate the vehicle within the costomer complaint conditions

as noted.

4. Using the Scan Tool, monitor “DTC” info for DTC 87 or 88.

-Refer to

Diagnostic Aids

Go to step 3

1. Ignition OFF.

2. Remove the A/C Compressor Clutch Rela y from the

Underhood Electrical Center.

3. Ignition ON, Engine OFF.

4. Using a Digital Voltmeter (DVM), check for voltage on the

Fused pins of the A/C Compressor Clutch Relay connector.

Does the DVM read the following value?

12 Volts Go to Step 5 Go to Step 4

Check the suspect circuit(s) between the A/C Compressor

Clutch Relay connector and the Fuse for the following

conditions:

•A short to ground

•An open circuit

•A short to voltage

Was the problem found?

-Verify Repair -

STEP ACTION VALUE(S) YES NO

1. Ignition OFF.

2. Disconnect the Engine Control Module (ECM) connectors

from the ECM.

3. Check the A/C Compressor Clutch Relay control circuit

between the ECM and Underhood Electrical Center for the

following conditions:

•A Short to ground

•An open circuit

•A short to voltage

Was the problem found?

-Verify Repair Go to Step 6

1. Reinstall the A/C Compressor Clutch Relay.

2. Using a fused jumper, ground the A/C Compressor Clutch

Relay control circuit at the ECM connector.

3. Ignition ON, Engine OFF.

Does the A/C Compressor turn ON?

-Go to Step 9 Go to Step 7

1. Ignition OFF.

2. Check the A/C Compressor Clutch circuit between the A/C

Compressor Clutch Relay and A/C Compressor Clutch for

the following conditions:

•A Short to ground

•An open circuit

•A short to voltage

Was the problem found?

-Verify Repair Go to Step 8

8Replace the A/C Compressor Clutch Relay.

Is the action complete? -Verify Repair -

9 Replace the EPROM or ECM. Note) Refer to 6E1-243 - --

ELECTRONIC IGNITION SYSTEM

DIAGNOSIS

If the engine cranks but will not run or immediately

stalls, the Engine Cranks But Will Not Start chart

must be used to determine if the failure is in the

ignition system or the fuel system. If DTC19, or

DTC18 is set, the appropriate diagnos tic trouble c ode

chart must be used for diagnosis.

If a misfire is being experienced refer to the

Symptoms section for diagnosis.

EVAP CANISTER PURGE

CONTROL SOLENOID (IF

APPLICABLE)

A continuous purge condition with no purge

commanded by the ECM will set a DTC62. Refer to

the DTC charts for further information.

VISUAL CHECK OF THE

EVAPORATIVE EMISSION

CANISTER (IF APPLICABLE)

•If the canister is cracked or damaged, replace the

canister.

•If fuel is leaking from the canister, replace the

canister and check hoses and hose routing.

IDLE AI R CONTROL (I AC) VALVE

The Scan Tool displays the IAC pintle position in

counts. A count of “O” indicates the ECM is

commanding the IAC pintle to be driven all the way

into a fully-seated position. This is usually caused by

a vacuum leak.

The higher the number of counts, the more air is

being comm anded to bypass the throttle blade. Ref er

to IAC System Check in order to diagnose the IAC

system. Refer to Rough, Unstable, or Incorrect

Idle, Stalling in Symptoms for other possible causes

of idle problems.

FUEL SYSTEM PRESSURE TEST

A fuel system pressure test is part of several of the

diagnostic charts and symptom checks. To perform

this test, refer to Fuel System Diagnosis.

FUEL METERING SYSTEM CHECK

Some failures of the fuel metering system will result

in an “Engine Cranks But Will Not Run” symptom. If

this condition ex ists , r ef er to the Cranks But Will Not

Run chart. This chart will determine if the problem is

caused by the ignition system, the ECM, or the fuel

pump electrical circuit.

Refer to Fuel System Electrical Test for the fuel

system wiring schematic.

If there is a fuel delivery problem, refer to Fu el System

Diagnosis, which diagnoses the fuel inj ectors, the fuel

pressure regulator, and the fuel pump.

Followings are applicable to the vehicles with

closed Loop S y ste m:

If a malfunction occurs in the fuel metering system, it

usually results in either a rich HO2S signal or a lean

HO2S signal. This condition is indicated by the HO2S

voltage, which causes the ECM to change the fuel

calculation (fuel injector pulse width) based on the

HO2S reading. Changes made to the fuel calculation

will be indicated by a change in the long term fuel trim

values which can be m onitor ed with a Scan T ool. Ideal

long term fuel trim values are around 0%; for a lean

HO2S signal, the ECM will add fuel, resulting in a fuel

trim value above 0%. Some variations in fuel trim

values are normal because all engines are not exactly

the same. If the evapor ative em ission c anister pur ge is

02 status may be rich condition. 02 status indic ates the

lean condition, refer to DTC44 for items which can

cause a lean HO2S signal.

FUEL INJECTOR COIL TEST

PROCEDURE AND FUEL

INJECTOR BALANCE TEST

PROCEDURE

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart:

2. Relieve the fuel pressure by connecting 5-8840-

0378-0 T-Joint to the fuel pressure connection on

the fuel rail.

CAUTION: In order to reduce the risk of fire

and personal injury, wrap a shop towel

around the fuel pressure connection. The

tow el will absorb any fuel leakage that occurs

during the connection of the fuel pressure

gauge. Place the towel in an approved

container when the connection of the fuel

pressure gauge is complete.

Place the fuel pressure gauge bleed hose in an

approved gasoline container.

With the ignition switch OFF open the valve on the

fuel pressure gauge.

3. Record the lowest voltage displayed by the DVM

after the first second of the test. (During the first

second, voltage displayed by the DVM may be

inaccurate due to the initial current surge.)

Injector Specifications:

RESISTANCE

OHMS VOLTAGE

SPECIFICATION AT

10°C-35°C (50°F-95°F)

11.8-12.6 5.7-6.6

•The voltage displayed by the DVM should be

within the specified range.

•The voltage displayed by the DVM may

increase throughout the test as the fuel injector

windings warm and the resistance of the fuel

injector windings changes.

•An erratic voltage reading (large fluctuations in

voltage that do not stabilize) indicates an

intermittent connection within the fuel injector.

5. Injector Specifications:

HIGHEST ACCEPTABLE

VOLTAGE

READING

ABOVE/BELOW

35°C/10°C (95°F/50°F)

ACCEPTABLE

SUBTRACTED

VALUE

9.5Volts 0.6Volt

7. The Fuel Injector Balance Test portion of this

chart (Step 7 through Step 11) checks the

mechanical (fuel delivery) portion of the fuel

injector . An engine cooldown period of 10 minutes

is necessary in order to avoid irregular fuel

pressure readings due to “Hot Soak” fuel boiling.

INJECTOR COIL TEST PROCEDURE (STEPS 1-6)

AND INJECTOR BALANCE TEST PROCEDURE (STEPS 7-11)

CYLINDER

1234

1st Reading (1) 296kPa

(43psi) 296kPa

(43psi)

2nd Reading (2) 205kPa

(29psi) 205kPa

(29psi) 196kPa

(28psi) 274kPa

(39psi)

Amount of Drop

(1st Reading-2nd Reading) 91kPa

(14psi) 91kPa

(14psi) 100kPa

(15psi) 22kPa

(4psi)

Av. Drop = 166kPa/24psi

±10kPa/1.5psi

= 156 − 176kPa or

22.5 − 25.5psi

Faulty, Lean

(Too Little

Fuel Drop)

Faulty, Lean

(Too Little

Fuel Drop)

Faulty, Lean

(Too Little

Fuel Drop)

Faulty, Lean

(Too Little

Fuel Drop)

NOTE: These figures are examples only.

INJECTOR COIL TEST PROCEDURE (STEPS 1-6) AND

INJECTOR BALANCE TEST PROCEDURE (STEPS 7-11)

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -Go to Step 2

Go to OBD

System Check

1. Turn the engine OFF.

Notice: In order to prevent flooding of a single cylinder and

possible engine damage, relieve the fuel pressure before

performing the fuel injector coil test procedure.

2. Relieve the fuel pressure. Refer to Test Description Number 2.

3. Connect the 5-8840-2618-0 Fuel Injector Tester to B+ and

ground, and to the 5-8840-2589-0 Injector Adapter Cable.

4. Remove the harness connector of the Fuel Injector and connect

the 5-8840-2589-0 Injector Adapter Cable for F/I check.

5. Set the amperage supply selector switch on the fuel injector

tester to the “Coil Test” 0.5 amp position.

6. Connect the leads from the 5-8840-2392-0 Digital Voltmeter

(DVM) to the fuel injector tester. Refer to the illustrations

associated with the test description.

7. Set the DVM to the tenths scale (0.0).

8. Observe the engine coolant temperature.

Is the engine coolant temperature within the specified values?

10°C (50°F)

35°C (95°F) Go to Step 3 Go to Step 5

1. Set the injector adapter cable to injector #1.

2. Press the “Push to Start Test” button on the fuel injector tester.

3. Observe the voltage reading on the DVM.

IMPORTANT: The voltage reading may rise during the test.

4. Record the lowest voltage observed after the first second of the

test.

5. Set the injector adapter cable to the next injector and repeat

steps 2, 3, and 4.

Did any fuel injector have an erratic voltage reading (large

fluctuations in voltage that did not stabilize) or a voltage reading

outside of the specified values? 5.7-6.6V Go to Step 4 Go to Step 7

4Replace the faulty fuel injector(S). Refer to Fuel Injector.

Is the action complete? -Go to Step 7 -

STEP ACTION VALUE(S) YES NO

1. Set the Injector Adapter Cable to injector #1.

2. Press the “Push to Start Test” button on the fuel injector tester.

3. Observe the voltage reading on the DVM.

IMPORTANT: The voltage reading may rise during the test.

4. Record the lowest voltage observed after the first second of the

test.

5. Set the Injector Adapter Cable to the next injector and repeat

steps 2, 3, and 4.

Did any fuel injector have an erratic voltage reading (large

fluctuations in voltage that did not stabilize) or a voltage reading

above the specified value? 9.5V Go to Step 4 Go to Step 6

1. Identify the highest voltage reading recorded (other than those

above 9.5V).

2. Subtract the voltage reading of each injector from the highest

voltage selected in step 1. Repeat until you have a subtracted

value for each injector.

For any injector, is the subtracted value in step 2 greater than the

specified value? 0.6V Go to Step 4 Go to Step 7

CAUTION: In order to reduce the risk of fire and personal

injury, wrap a shop towel around the fuel pressure connection.

The towel will absorb any fuel leakage that occurs during the

connection of the fuel pressure gauge. Place the Towel in an

approved container when the connection of the fuel pressure

gauge is complete.

1. Connect the 5-8840-0378-0 Fuel Pressure Gauge to the fuel

pressure test port.

2. Energize the fuel pump using the Scan Tool.

3. Place the bleed hose of the fuel pressure gauge into an

approved gasoline container.

4. Bleed the air out of the fuel pressure gauge.

5. With the fuel pump running, observe the reading on the fuel

pressure gauge.

Is the fuel pressure within the specified values?

296kPa-

376kPa

(43-55psi) Go to Step 8

Go to

Fuel System

Diagnosis

8Turn the fuel pump OFF.

Does the fuel pressure remain constant? -

Go to Step 9

Go to

Fuel System

Diagnosis

STEP ACTION VALUE(S) YES NO

1. Connect the 5-8840-0378-0 Fuel Injector Tester and 5-8840-

2589-0 Injector Adapter Cable to the fuel injector harness

connector.

2. Set the amperage supply selector switch on the fuel injector

tester to the “Balance Test” 0.5-2.5 amp position.

3. Using the Scan Tool turn the fuel pump ON then OFF in order

to pressurize the fuel system.

4. Record the fuel pressure indicated by the fuel pressure

gauge after the fuel pressure stabilizes.

This is the first pressure reading.

5. Energize the fuel injector by depressing the “Push to Start

Test” button on the fuel injector tester.

6. Record the fuel pressure indicated by the fuel pressure

gauge after the fuel pressure gauge needle has stopped

moving. This is the second pressure reading.

7. Repeat steps 1 through 6 for each fuel injector.

8. Subtract the second pressure reading from the first pressure

reading for one fuel injector. The result is the pressure drop

value.

9. Obtain a pressure drop value for each fuel injector.

10. Add all of the individual pressure drop values.

This is the total pressure drop.

11. Divide the total pressure drop by the number of fuel injectors.

This is the average pressure drop.

Does any fuel injector have a pressure drop value that is either

higher than the average pressure drop or lower than the average

pressure drop by the specified value? 10kPa

(1.5psi) Go to Step 10

Go to OBD

System Check

Re-test any fuel injector that does not meet the specification. Refer

to the procedure in step 11.

Notice: Do not repeat any portion of this test before running the

engine in order to prevent the engine from flooding.

Does any fuel injector still have a pressure drop value that is either

higher than the average pressure drop or lower than the average

pressure drop by the specified value? 10kPa

(1.5psi) Go to Step 11

Go to

Symptoms

1. Replace the faulty fuel injector(s). Refer to Fuel Injector.

2. Disconnect the 5-8840-2589-0 Injector Adapter Cable for F/I

check and re-connect the original F/I check connector.

Is the action complete? -

Verify repair

ENGINE CONTROL MODULE

(ECM) DI AGNOSIS

To read and clear diagnostic trouble codes, use a

Scan Tool.

IMPORTANT: Use of a Sc an Tool is rec omm ended to

clear diagnostic trouble codes f rom the ECM m emor y.

Diagnostic trouble codes can also be cleared by

turning the ignition OFF and disconnecting the battery

power from the ECM for 30 seconds. Turning off the

ignition and disconnecting the battery power from the

ECM will cause all diagnostic information in the ECM

memory to be cleared. Therefore, all the diagnostic

tests will have to be re-run.

Since the ECM can have a failure which may affect

only one c ircuit, following the diagnostic procedures in

this section will determ ine which circuit has a problem

and where it is.

If a diagnostic chart indicates that the ECM

connections or the ECM is the cause of a problem,

and the EPROM or ECM is r eplaced, but this does not

correct the problem, one of the following may be the

reason:

•There is a problem with the ECM terminal

connections. The terminals may have to be

rem oved from the connector in order to check them

properly.

•The problem is intermittent. This means that the

problem is not present at the time the system is

being checked. In this c ase, ref er to the Symptoms

portion of the manual and make a careful physical

inspection of all components and wiring associated

with the affected system.

•There is a shorted solenoid, relay coil, or harness.

Solenoids and relays are turned ON and OFF by the

ECM using internal electronic switches called

drivers. A shorted solenoid, relay coil, or harness

will not damage the ECM but will cause the solenoid

or relay to be inoperative.

MULTIPLE ECM INFORM ATION

SENSOR DTCS SET

CIRCUIT DESCRIPTION

The engine control module (ECM) monitors various

sensors to determine the engine operating conditions.

The ECM controls fuel delivery, spark advance, and

emission control device operation based on the sensor

inputs.

The ECM provides a sensor ground to all of the

sensors. The ECM applies 5 volts through a pull-up

resistor, and determines the status of the following

sensors by monitoring the voltage present between

the 5-volt supply and the resistor:

•The throttle position (TP) sensor

•The manifold absolute pressure (MAP) sensor

The ECM provides the following sensors with a 5-volt

reference and a sensor ground signal:

•Intake Air Temp Sensor (IAT).

•Engine Coolant Temp Sensor (ECT).

•Manifold Absolute Pressure Sensor (MAP).

•Throttle Position Sensor (TPS).

The ECM monitors the separate feedback signals

from these sensors in order to determine their

operating status.

DIAGNOSTIC AIDS

IMPORTANT: Be sure to inspect ECM and engine

grounds for being secure and clean.

A short to voltage in one of the sensor input circuits

may cause one or more of the following DTCs to be

set:

•21/33

IMPORTANT: If a sensor input circuit has been

shorted to voltage, ensure that the sensor is not

damaged. A dam aged sensor will continue to indicate

a high or low voltage after the affected circuit has

been repaired. If the sensor has been damaged,

replace it.

A short to ground in the circuit between ECM and

sensors will cause one or more of the following DTCs

to be set:

•14/22

•34/69

Check for the following conditions:

POOR CONNECTION AT ECM.

Inspect the harness connectors for backed-out

terminals, improper mating, broken locks, improperly

form ed or damaged term inals, and a poor terminal-to-

wire connection.

DAMAGED HARNESS.

Inspect the wiring harness for damage. If the harness

is not damaged, observe an affected sensor's

displayed value on the Scan Tool with the ignition ON

and the engine OFF while you move the connectors

and the wiring harnesses related to the following

sensors:

•IAT

•ECT

•TPS

•MAP

MULTIPLE ECM INFORMATION SENSOR DTCS SET

STEP ACTION VALUE(S)

YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -Go to Step 2

Go to OBD

System Check

1. Turn the ignition OFF disconnect the ECM.

2. Turn the ignition ON check the 5 volt reference circuits for the

following conditions:

•A poor connection at the ECM.

•An open between the ECM connector and the splice.

•A short to ground.

•A short to voltage.

Is there an open or short?

Go to Step 3 Go to Step 4

3Repair the open or short.

Is the action complete? -Verify repair -

Check the sensor ground circuit for the following conditions:

•A poor connection at the ECM or the affected sensors.

•An open between the ECM connector and the affected sensors.

Is there an open or a poor connection? -

Go to Step 5 Go to Step 6

5Repair the open or the poor connection.

Is the action complete? -Verify repair -

6Measure the voltage between the MAP sensor signal circuit at the

ECM harness connector and ground.

Does the voltage measure near the specified value? 0V

Go to Step 7 Go to Step 10

7Measure the voltage between the TP sensor signal circuit at the

ECM harness connector and ground.

Does the voltage measure near the specified value? 0V

Go to Step 8 Go to Step 11

8Measure the voltage between the IAT sensor signal circuit at the

ECM harness connector and ground.

Does the voltage measure near the specified value? 0V

Go to Step 9 Go to Step 12

9Measure the voltage between the ECT sensor signal circuit at the

ECM harness connector and ground.

Does the voltage measure near the specified value? 0V

Go to Step 14 Go to Step 13

10 Locate and repair the short to voltage in the MAP sensor signal

circuit.

Is the action complete? -

Verify repair

11 Locate and repair the short to voltage in the TP sensor signal

circuit.

Is the action complete? -

Verify repair

12 Locate and repair the short to voltage in the IAT sensor signal

circuit.

Is the action complete? -

Verify repair

13 Locate and repair the short to voltage in the ECT sensor signal

circuit.

Is the action complete? -

Verify repair

14 Replace the EPPROM or ECM. Note) Refer to 6E1-243 -Go to OBD

System Check -

ENGINE SCAN TOOL DATA

DEFINITI ONS AND RANGES

A/C CLUTCH - Scan Tool Displays ON or OFF -

Indicates whether the ECM has commanded the A/C

clutch ON. Used in A/C system diagnostics.

A/C REQUEST - Scan Tool Displays NO or OFF -

Indicates the state of the A/C reques t input cir cuit from

the HVAC controls. The ECM uses the A/C request

signal to determine whether A/C compressor operation

is being requested.

AIR/FUEL RATIO - Scan Tool Range 0-0:1-25.5:1 -

Air/fuel ratio indicates the ECM commanded value. In

“Closed Loop” , the air/fuel ratio should normally be

displayed around “14.2-14.7” . A lower air/fuel ratio

indicates a richer commanded mixture, which may be

seen during power enrichment or TWC (If applicable)

protection modes. A higher air/fuel ratio indicates a

leaner commanded mixture. This can be seen during

deceleration fuel mode.

BARO kPa - Scan Tool Range 10-105 - The

barometric pressure reading is determined from the

MAP sensor signal monitored during key up and wide

open throttle (WOT) conditions. The barometric

pressure is used to compensate for altitude

differences and is normally displayed around “61-104”

depending on altitude and barometric pressure.

DECELERATION FUEL CUT OFF - YES or NO-

Scan Tool Displays - “ACTIVE” displayed indicates

that the ECM has detected conditions appropriate to

operate in deceleration fuel mode. The ECM will

command the deceleration fuel mode when it detects

a closed throttle position while the vehicle is traveling

over 20 m ph. W hile in the deceleration f uel m ode, the

ECM will decrease the amount of fuel delivered by

entering “Open Loop” and decreasing the injector

pulse width.

DESIRED IDLE - Scan Tool Range 0-3187 RPM -

The idle speed that the ECM is commanding. The

ECM will compensate for various engine loads based

on engine coolant temperature, to keep the engine at

the desired speed.

ECT TEMP. - (Engine Coolant Temperature) Scan

Tool Range −

−−

−40°C to 151°C (−

−−

−40°F to 304°F) - The

engine coolant temperature (ECT) is mounted in the

coolant stream and sends engine temperature

information to the ECM. The ECM applies 5 volts to

the ECT sensor circuit. The sensor is a thermistor

which changes internal resistance as the temperature

changes. When the sensor is cold (high resistance),

the ECM monitor s a high signal voltage and interprets

that as a cold engine. As the sensor warms

(decreasing resistance), the voltage signal will

decrease and the ECM will interpret the lower voltage

as a warm engine.

TIME FROM START - Scan Tool Range 00:00:00-

99:99:99 Hrs:Min:Sec - Indicates the time elapsed

since the engine was star ted. If the engine is stopped,

engine run time will be reset to 00:00:00.

ENGINE SPEED - Range 0-9999 RPM - Engine

speed is computed by the ECM form the 58X

reference input. It should remain close to desired idle

under various engine loads with engine idling.

EVAP PURGE PWM (If applicable) - Scan Tool

Range 0%-100% - Represents the ECM commanded

PWM duty cycle of the EVAP purge solenoid valve.

“0%” displayed indicates no purge; “100%” displayed

indicates full purge.

FUEL PUMP RELAY - Scan Tool Displays ON or

OFF - Indicates the ECM comm anded s tate of the f uel

pump relay driver circuit.

02 BLM CELL NUMBER (If applicable)- Scan Tool

Range 0-21 - The 02 BLM cell is dependent upon

engine speed and MAP sensor readings. A plot of

RPM vs. MAP is divided into 22 cells. 02 BLM cell

indicates which cell is currently active.

B1 HO2S BANK 1 (If applicable)- Scan Tool Range

0-1000 mV - Represents the fuel control exhaust

oxygen sensor output voltage. Should fluctuate

constantly within a range between 10 mV (lean

exhaust) and 1000 mV (rich exhaust) while operating

in “Closed Loop” .

B1 HO2S READY BANK 1 (If applicable)- Scan Tool

Displays YES or NO - Indicates the status of the

exhaust oxygen sensor. The Scan Tool will indicate

that the exhaust oxygen sensor is ready when the

ECM detects a fluctuating HO2S voltage sufficient to

allow “Closed Loop” operation. This will not occur

unless the exhaust sensor is warmed up.

IAC CONTROL STEP - Scan Tool Range 0-255

steps - Displays the commanded position of the idle

air control pintle in counts. A larger number of counts

means that more air is being comm anded through the

idle air passage. Idle air control should respond fairly

quickly to changes in engine load to maintain desired

idle RPM.

IAT (INTAKE AIR TEMPERATURE) - Scan Tool

Range −

−−

−40°C to 151°C (−

−−

−40°F to 304°F) - The ECM

converts the resistance of the intake air temperature

sensor to degrees. Intake air temperature (IAT) is

used by the ECM to adjust fuel delivery and spark

timing according to incoming air density.

BATTERY - Scan Tool Range 0-25.5 Volts - This

represents the system voltage measured by the ECM

at its ignition feed.

INJ. PULSE WIDTH - Scan Tool Range 0-1000

msec. - Indicates the amount of time the ECM is

commanding each injector ON during each engine

cycle. A longer injector pulse width will cause more

fuel to be delivered. Injector pulse width should

increase with increased engine load.

FUELING MODE (If applicable) - Scan Tool

Displays OPEN or CLOSED - “CLOSED” indicates

that the ECM is controlling fuel delivery according to

oxygen sensor voltage. In “OPEN” the ECM ignores

the oxygen sensor voltage and bases the amount of

fuel to be delivered on T P s ensor, and engine coolant,

sensor inputs only.

MAP - Scan Tool Range 10-105 kPa (0.00-4.97

Volts) - The manif old abs olute pr ess ur e (MAP) s ens or

measures the change in the intake manifold pressure

from engine load, and speed changes. As intake

manifold pressure increases, intake vacuum

decreases, resulting in a higher MAP sensor voltage

and kPa reading. The MAP sensor signal is used to

monitor intake manifold pressure changes to update

the BARO reading, and as an enabling factor for

several of the diagnostics.

CEL-CHECK ENGINE LIGHT - Scan Tool Displays

ON or OFF - Indicates the ECM commanded state of

the malfunction indicator lamp (“Check Engine

Lamp”).

02 STATUS (If applicable) - Scan Tool Displays

RICH or LEAN - Indicates whether oxygen sensor

voltage is above a 600 mV thr eshold voltage (“R ICH” )

or below a 3000 mV threshold voltage (“LEAN” ).

Should change constantly while in “Closed Loop” ,

indicating that the ECM is controlling the air/fuel

mixture properly.

ELECTRIC SPARK CONTROL - Scan Tool Range

−

−−

−64°CA to 64°CA - Displays the amount of spark

advance being commanded by the ECM on the IC

circuit.

THROTT L E POSITION - Scan Tool Ran ge 0%-100%

- TP (throttle position) angle is computed by the ECM

from the TP sensor voltage. TP angle should display

“0%” at idle and “100%” at wide open throttle.

TPS SIGNAL - Scan Tool Range 0.00-5.00 Volts -

The voltage being monitored by the ECM on the TP

sensor signal circuit.

TYPICAL SCAN DATA VALUES

Use the T ypical Scan Data Values Table only after the

On- Board Diagnostic System Check has been

completed, no DTC(s) were noted, and you have

determined that the on-board diagnostics are

functioning properly. Scan Tool values from a

properly-running engine may be used for comparison

with the engine you are diagnosing. The typical scan

data values represent values that would be seen on a

normally-running engine.

Notice: A Scan Tool that displays faulty data should

not be used, and the problem should be reported to

the Scan Tool manufac tur er. Us e of a f aulty Scan Tool

can result in misdiagnosis and unnecessary

replacement of parts.

Only the parameters listed below are r ef er r ed to in this

service manual for use in diagnosis. For further

information on using the Scan Tool to diagnose the

ECM and related sensors, refer to the applicable

reference section listed below. If all values are within

the typical range described below, refer to the

Symptoms section for diagnosis.

TEST CONDITIONS

Engine running, lower radiator hose hot, transmission

in park or neutral, “Closed Loop” (If applicable),

accessories OFF, brake not applied and air

conditioning OFF.

2.2L/2.0L L-4 ENGINE

SCAN TOOL

PARAMETER DATA LIST UNITS

DISPLAYED TYPICAL DATA

VALUES (IDLE) TYPICAL DATA

VALUES

(2500 RPM)

REFER TO

A/C Clutch Engine On/Off Off Off General Description and

Operation, A/C Clutch Circuit

Operation

A/C Request Engine No/Off Off Off General Description and

Operation, A/C Request

Signal

Air/Fuel Ratio

(If applicable) Engine Ratio: _to 1 14.6:1 14.6:1 General Description and

Operation, Fuel System

Metering Purpose

BARO kPa Engine kPa 103 (depends on

altitude and

barometric)

103 (depends on

altitude and

barometric)

General Description and

Operation

Broadcast Code

‘PROM’

Identification

Engine 5 Figures Depends on

latest level of

engine

software and

calibration.

Review Technical

Service Bulletins

for most current

level.

Depends on latest

level of engine

software and

calibration.

Review Technical

Service Bulletins

for most current

level.

Decel Fuel Mode Engine Active/

Inactive Inactive Inactive General Description and

Operation, Deceleration Mode

Desired Idle Engine RPM 825 - General Description and

Operation, Idle Air Control

(IAC) Valve

ECT

(Engine Coolant

Temp)

Engine Degrees C,

Degrees F 80-100°C

(176-212°F) 80-100°C

(176-212°F) General Description and

Operation, Engine Coolant

Temperature (ECT) Sensor

Time From Start Engine Hrs:Min:Sec Varies. Resets at

each engine start. Varies. Resets at

each engine start. -

Engine Speed Engine RPM Within −50 to

+100

of “Desired Idle”

Actual engine

speed -

EVAP Purge

PWM

(If applicable)

Engine Percent 0% 0% Diagnosis, EVAP Emission

Canister Purge Valve Check

Fuel Pump Engine On/Off On On Engine Fuel

02 BLM

Cell Number

(If applicable)

Engine Cell number 20 5 Diagnosis, Fuel Trim Cell

Diagnostic Weights

HO2S

(If applicable)

(millivolts)

Engine Millivolts 160-800 changing

quickly 160-800, always

changing quickly General Description and

Operation, Fuel Control HO2S

SCAN TOOL

PARAMETER DATA LIST UNITS

DISPLAYED TYPICAL DATA

VALUES (IDLE) TYPICAL DATA

VALUES

(2500 RPM)

REFER TO

HO2S

(If applicable)

(ready/

not ready)

Specific Eng:

HO2S Ready/

Not Ready Ready Ready General Description and

Operation, Fuel Control

HO2S; DTC: DTC13

IAT

(Intake Air Temp) Engine Degrees C,

Degrees F 0-100°C,

(32°F-212°F)

depends

on underhood

0-80°C, depends

(32°F-176°F)

on underhood

General Description and

Operation, Intake Air

Temperature (IAT) Sensor

Battery Engine Volts 14 34 General Description and

Operation, Electronic Ignition

System

Inj. Pulse Engine Milliseconds 1.8-1.9 1.4-1.5 General Description, Fuel

Metering, Fuel Injector

Fueling Mode

(If applicable) Engine Open/Closed Closed Closed General Description and

Operation, Fuel Me tering

System; DTCs: DTC13

MAP kPa

(Manifold

Absolute

Pressure)

Engine Kilopascals 37 29 General Description and

Operation, Manifold Absolute

Pressure (MAP) Sensor;

DTCs: DTC33/34

CEL Engine On/Off Off Off On-Board Diagnostic System

Check

PSP Switch

(Power Steering

Pressure)

Engine ON/OFF - - Power Steering Gear and

Pump, General Description,

Pressure Switch

02 STATUS

(If applicable) Engine Rich/Lean Always changing Always changing General Description and

Operation, Fuel Control HO2S

Electric spark

control Engine Degrees

Before Top

Dead Center

14 34 General Description and

Operation, Electronic Ignition

System

(Throttle Position) Engine Degrees open 0 5 General Description and

Operation, Throttle Position

(TP) Sensor; DTCs: DTC

21/22

TP Sensor

(Throttle Position) Engine Volts 0.80 1.02 General Description and

Operation, Throttle Position

(TP) Sensor; DTCs: DTC

21/22

Vehicle Speed Engine km/h 0 0

GENERAL DESCRIPTION

(EVAPORATIVE (EVAP) EMISSION

SYSTEM) (IF APPLICABLE)

EVAP EMISSION CONTROL SYSTEM

PURPOSE

The basic Evaporative Emission (EVAP) Control

System used on all vehicle is the charcoal canister

storage method. This method transfers fuel vapor

from the fuel tank to an activated carbon (charcoal)

storage device (canister) to hold the vapors when the

vehicle is not operating. When the engine is running,

the fuel vapor is purged from the carbon element by

intake air flow and consumed in the normal

combustion process.

VAPO R CANISTER

Gasoline vapors from the fuel tank flow into the tube

labeled tank. Any liquid fuel goes into a reservoir in the

bottom of the canister to protect the integrity of the

carbon bed. These vapors are absorbed into the

carbon. The canister is purged when the engine is

running or commanded by Engine Control Module

(ECM). Ambient air is allowed into the canister through

the air tube in the top. The air mixes with the vapor

and the mixture is drawn into the intake manifold.

EVAP CONTROL SYSTEM

The solenoid used with this canister uses Vacuum

Switch Valve to control purge. The ECM opens and

closes the solenoid to control purge.

The ECM operates a Normally Closed (N/C) solenoid

valve which controls the vac uum to pur ge the char c oal

canister. Under cold engine or idle conditions, the

solenoid is not energized by the ECM, which blocks

vacuum to purge the canister.

The ECM energizes the solenoid valve and allows

purge when:

•Engine is warm above 69°C (156°F)

•After the engine has been running a specified time.

LEGEND

(1) Vapor from Fuel Tank

(2) Evaporate Emission Canister Purge Vacuum

(3) Canister Body

(4) Carbon

(5) Filter

(6) Grid

(7) Air Flow During Purge

•Throttle position is above 7% throttle position

sensor.

RESULTS OF INCORRECT OPERATION

Poor idle, stalling and poor driveability can be caused

by:

•Inoperative purge solenoid.

•Damaged canister.

•Hoses split, cracked and/or not connected to the

proper tubes.

Evidence of f uel los s or f uel vapor odor c an be c aused

by:

•Liquid fuel leaking from fuel lines, or fuel pump.

•Cracked or damaged canister.

•Disconnected, misrouted, kinked, deteriorated or

damaged vapor hoses, or control hoses.

If the solenoid is always open, the canister can purge

to the intake manif old at all tim es. This can allow extra

fuel at idle or dur ing war m-up, which can cause rough

or unstable idle, or too rich operation.

If the solenoid is always closed, the canister can

become over-loaded, resulting in fuel odor.

DIAGNOSIS

;;

;

LEGEND

(1) Intake Manifold

(2) Fuel Vapor Purge Control Solenoid

(3) Fuel Vapor Canister

(4) Check and Relief valve

(5) Fuel Tank

(6) Pressure/ Vacuum Vented

(7) Rollover Valve

VISUAL CHECK OF CANISTER

Cracked or damaged, replace canister.

EVAPORATIVE EMISSION CANISTER PURGE CONTROL SOLENOID VALVE

CHECK (IF APPLICABLE)

ENGINE

CONTROL

MODULE

(ECM)

ENGINE FUSE

15A

IGNITION

EVAPORETIVE

EMISSION

CANISTER PURGE

SOLENOID

CONTROL DRIVER

EVAPORATIVE

EMISSION

CANISTER

PURGE CONTLOL

SOLENOID VALVE

N.C.

MANIFOLD

VACUUM

TO CANISTER

CIRCUIT DESCRIPTION:

The EVAP canister purge is controlled by a solenoid

valve that allows the manifold vacuum to purge the

canister . The engine control m odule (ECM) supplies a

ground to energize the solenoid valve (purge on). The

EVAP purge solenoid control is pulse- width

modulated (PWM) (turned on and off several times a

second). The duty cycle ( pulse width) is determined by

engine operating conditions including load, throttle

position, coolant temperature and ambient

temper ature. The duty cyc le is calculated by the ECM.

The output is commanded when the appropriate

conditions have been met. These condi-tions are:

•The engine is fully warmed up.

•The engine has been running for a specified time.

•The IAT reading is above 10°C (50°F).

The EVAP purge vacuum switch is a normally closed

switch positioned in the purge line between the

canister and the EVAP purge control solenoid valve.

A continuous purge condition with no purge

commanded by the ECM will set a DTC62.

Poor idle, stalling and poor driveability can be caused

by:

•A malfunctioning purge solenoid.

•A damaged canister.

•Hoses that are split, cracked, or not connected

properly.

TEST DESCRIPTION:

Numbers below refer to circled numbers on the

diagnostic chart.

1. Check to see if the solenoid is opened or closed.

The solenoid is normally de-energized in this step,

so it should be closed.

2. Check to determine if solenoid was open due to

electrical CKT problem or defective solenoid.

3. Completes functional check by grounding test

terminal. This should normally energize the

solenoid opening the valve which should allow the

vacuum to drop (purge “ON“).

DIAGNOSTIC AIDS:

Make a visual check of vacuum hose(s). Check

throttle body for possible cracked, or plugged vacuum

block.

Malfunction indicator lamp for possible mechanical

problem.

GENERAL DESCRIPTION

LEGEND

(1) Filler Cap

(2) Fuel Tank

(3) Rollover Valve

(4) Fuel Pump

(5) Fuel Filter

(6) Fuel Rail

(7) Intake Manifold

(8) Fuel Pressure Regulator

(9) Duty Solenoid Valve (Evap. Purge Control

Solenoid)

(10) Throttle Valve

(11) Canister

(12) Check and Relief Valve

(13) Drain Hose

(14) 2 Way Valve

ECM DIAGNOSTI C TROUBLE CODES

The following table lists the diagnostic trouble codes

supported a Tech 2 and to flash. If any DTCs not listed

here are displayed by a Tech 2, the Tech 2 data may

be faulty; notify the T ech 2 manuf acturer of any DTCs

displayed that are not included in the following table.

ECM DIAGNOSTIC TROUBLE CODES

DTC USING A

TECH 2 FLASH DTC DESCRIPTION ILLUMINATE MIL

22 22 Throttle position low yes

21 21 Throttle position high yes

13 13 Oxygen sensor not ready (If applicable) yes

44 44 Oxygen sensor too lean (If applicable) yes

45 45 Oxygen sensor rich too long (If applicable) yes

14 14 Coolant High yes

15 15 Coolant Low yes

16 16 Knock sensor disconnected circuit open yes

18 18 Digital Signal to Noise Enhancement Filter failure yes

19 19 58X signal incorrect yes

24 24 Vehicle Speed Senser fault yes

33 33 Manifold Absolute Pressure Sensor too high yes

34 34 MAP too low yes

49 49 Batt voltage too high yes

69 69 Intake Air Temp. Sensor too high yes

71 71 IAT too low yes

17 17 Injector malf yes

41 41 Coil Driver B short to battery yes

42 42 Coil Driver A short to battery yes

63 63 Coil Driver B short to ground yes

64 64 Coil Driver A short to ground yes

35 35 Idle Air Control Value error yes

56 56 Check Engine Lamp low error yes

57 57 Check Engine Lamp high error yes

61 61 Charcoal Canister Purge low error (If applicable) yes

62 62 CCP Solenoid high error (If applicable) yes

87 87 AC Clutch relay low error yes

88 88 AC Clutch relay high error yes

93 93 Quad Driver Sub Module error yes

51 51 EPROM error yes

55 55 EEPROM error yes

91 91 Tacho out low error yes

92 92 Tacho out high error yes

29 29 Fuel Pump relay shorted to ground yes

32 32 Fuel Pump relay shorted to battery yes

SYMPTOM DIAGNOSIS

PRELIMI NARY CHECKS

Before using this section, perform the "On-Board

Diagnostic (OBD) System Check" and verify all of the

following items:

•The engine control module (ECM) and malfunction

indicator lamp (MIL) (Check Engine lamp) are

operating correctly.

•There are no Diagnostic Trouble Code(s) stored.

•Scan Tool data is within normal operating range.

Refer to Typical Scan Data Values.

•Verify the customer complaint and locate the

correct symptom in the table of contents. Perform

the procedure included in the symptom chart.

VISUAL /PHYSICAL CHECK

Several of the symptom procedures call for a careful

visual/physical check. This can lead to correcting a

problem without further checks and can save valuable

time. This check should include the following items:

•ECM grounds for cleanliness, tightness and proper

location.

•Vacuum hoses for splits, kinks, and proper

connections, shown on the " Emission Control

Sys tem Schem atics". Chec k thoroughly for any type

of leak or restriction.

•Air intake ducts for collapsed or damaged areas.

•Air leaks at throttle body mounting area, manifold

absolute pressure (MAP) sensor and intake

manifold sealing surfaces.

•Ignition wires for cracking, hardness, and carbon

tracking.

•Wiring for proper connections, pinches and cuts.

INTERMITTENT

Important: An intermittent problem may or may not

turn on the malfunction indicator lamp (MIL) or store a

Diagnostic Trouble Code. DO NOT use the Diagnostic

Trouble Code (Diagnostic Trouble Code) charts for

intermittent problems. The fault must be present to

locate the problem.

Most intermittent problems are caused by faulty

electrical connections or wiring. Perform a careful

visual/physical check for the following conditions.

•Poor mating of the connector halves or a terminal

not fully seated in the connector (backed out).

•Improperly formed or damaged terminal.

•All connector ter m inals in the problem circ uit s hould

be carefully checked for proper contact tension.

•Poor terminal-to-wire connection. This requires

removing the terminal from the connector body to

check.

•Ignition coil shorted to ground and arcing at ignition

wires or plugs.

•MIL (Check Engine lamp) wire to ECM shorted to

ground.

•Poor ECM grounds. Refer to the

ECM wiring diagrams.

Road test the vehicle with a 5-8840-2392-0 Digital

Multimeter connected to a suspected circuit. An

abnormal voltage when the malfunction occurs is a

good indication that there is a fault in the circuit being

monitored.

Use a Scan Tool to help detect intermittent conditions.

The Scan Tools have several features that can be

used to locate an intermittent condition. Use the

following features to find intermittent faults:

To check for loss of diagnostic code memory,

disconnect the MAP sensor and idle the engine until

the MIL (Check Engine lamp) comes on. Diagnostic

Trouble Code 34 should be stored and kept in memory

when the ignition is turned "OFF." If not, the ECM is

faulty. When this test is completed, make sure that

you clear the Diagnostic Trouble Code 34 from

memory.

Check for improper installation of electrical options

such as lights, cellular phones, etc. Check all wires

from the ECM to the ignition control module for poor

connections.

Check for an open diode across the A/C compressor

clutch and check for other open diodes (refer to wiring

diagrams in Electrical Diagnosis).

If problem has not been found, refer to

ECM Connector Symptom tables.

HARD START SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Engine cranks, but does not start for a long time. Does eventually run, or may start but immediately stalls.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

Check engine coolant temperature (ECT) sensor for shift in

value.

1. After 8 hours with the hood up and the engine not running,

connect the Scan Tool.

2. Ignition ON, engine not running.

3. Using the Scan Tool, compare Engine Coolant Temperature

to Intake Air Temperature.

Are ECT and IAT within the specified value of each other? ±5°C

(±9°F) Go to Step 8 Go to Step 5

1. Using a Scan Tool, display the engine coolant temperature

and note the value.

2. Check the resistance of the engine coolant temperature

sensor.

3. Refer to Temperature vs. Resistance chart in Diagnostic

Trouble Code 14 for resistance specifications.

Is the actual resistance near the resistance value in the chart for

the temperature that was noted?

Go to Step 7 Go to Step 6

6Replace the ECT sensor.

Is the action complete? -Verify repair -

7Located and repair high resistance or connection in the ECT

signal circuit or the ECT signal circuit or the ECM sensor

ground. -

Verify repair

8Check for a faulty, plugged, or incorrectly installed PCV hoses.

Was a problem found? -

Verify repair Go to Step 9

Visually/Physically inspect the secondary ignition wires. Check

for the following conditions:

•Verify that all ignition wire resistance are less than the

specified value.

•Verify that ignition wires are correctly routed to eliminate

cross-firing.

•Verify that ignition wires are not arcing to ground.

Spraying the secondary ignition wires with a light mist of water

may help locate an intermittent problem.

Was a problem found?

#1 cyl. 4.7kΩ

#2 cyl. 3.9kΩ

#3 cyl. 3.4kΩ

#4 cyl. 3.1kΩVerify repair Go to Step 10

STEP ACTION VALUE(S) YES NO

10 Check for proper ignition voltage output with a spark tester (Use

commercially available tool).

Was a problem found? -

Verify repair Go to Step 11

1. Remove the spark plugs and check for gas or oil fouling

cracks, wear, improper gap, burned electrodes, heavy

deposits, or improper heat range.

If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 12

12 Check for a loose ignition control module ground.

Was a problem found? -Verify repair Go to Step 13

1. Check the ignition coil secondary resistance.

2. Replace the coil if it is greater than the specified resistance.

Did the coil require replacement? 2.5 kΩVerify repair Go to Step 14

14 Check IAC operation. Perform the procedure in the diagnostic

chart Diagnostic Trouble Code 35, Step 6.

Was a problem found? -

Verify repair Go to Step 15

15 Check for water or alcohol contaminated fuel.

Was a problem found? -Verify repair Go to Step 16

16 Perform the procedure in Fuel System Pressure Test to

determine if there is a problem with fuel delivery.

Was a problem found? -

Verify repair Go to Step 17

Check for the following engine mechanical problems (refer to

Engine Mechanical):

•Low compression

•Leaking cylinder head gaskets

•Worn camshaft

•Camshaft drive belt slipped or stripped

Was a problem found?

Verify repair Go to Step 18

1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection

•Scan Tool data

•All electrical connections within a suspected circuit and/or

system

Was a problem found?

Verify repair

Contact

Technical

Assistance

SURGES AND/OR CHUGGLES SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no

change in the accelerator pedal.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

Was a visual/physical check performed?

Go to Step 4

Go to Visual/

Physical

Check

Be sure that the driver understands A/C compressor operation

as explained in the owner's manual.

Inform the customer how the A/C clutch operate.

Is the customer experiencing a normal condition?

System OK Go to Step 5

Check the fuel control Heated Oxygen Sensor (HO2S) (If

applicable). When monitored on the Scan Tool, the HO2S

should respond quickly to different throttle positions. If it doesn't

check for silicon or other contaminants from fuel or use of

improper RTV sealant. The sensors may have a white powdery

coating. Silicon contamination sends a rich exhaust signal which

causes the ECM to command an excessively lean air/fuel

mixture.

Was a problem found?

Verify repair Go to Step 6

6Check the fuel pressure. Refer to Fuel System Pressure Test.

Was a problem found? -

Verify repair Go to Step 7

7Monitor "02 Status" on the Scan Tool (If applicable).

Is "02 Status" in the (rich condition)? -Go to Step 8 Go to Step 9

8Check items that can cause the engine to run rich.

Refer to Diagnostic Aids in Diagnostic Trouble Code 45 (If

applicable).

Was a problem found?

Verify repair Go to Step 10

9Check items that can cause the engine to run lean.

Refer to Diagnostic Aids in Diagnostic Trouble Code 44 (If

applicable).

Was a problem found?

Verify repair Go to Step 10

10 Check for proper ignition voltage output with the spark tester

(Use commercially available tool).

Was a problem found? -

Verify repair Go to Step 11

11 Check for a loose ignition control module ground.

Was a problem found? -Verify repair Go to Step 12

STEP ACTION VALUE(S) YES NO

Visually/Physically inspect the secondary ignition wires. Check

for the following conditions.

•Verify that all ignition wire resistance are less than the

specified value.

•Verify that ignition wires are correctly routed to eliminate

cross-firing.

•Verify that ignition wires are not arcing to ground.

Spraying the secondary ignition wires with a light mist of water

may help locate an intermittent problem.

Was a problem found?

#1 cyl. 4.7kΩ

#2 cyl. 3.9kΩ

#3 cyl. 3.4kΩ

#4 cyl. 3.1kΩVerify repair Go to Step 13

1. Check ignition coil secondary resistance.

2. Replace the coil if it is greater than the specified resistance.

Did the coil require replacement? 2.5 kΩVerify repair Go to Step 14

1. Remove the spark plugs and check for gas or oil fouling

cracks, wear, improper gap, burned electrodes, heavy

deposits or improper heat range.

2. If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 15

1. Check the injector connectors.

2. If any of the connectors are connected at an improper

cylinder, correct as necessary.

Was a problem found?

Verify repair Go to Step 16

Check the ECM grounds to verify that they are clean and tight.

Refer to the ECM wiring diagrams in Electrical Diagnosis.

Was a problem found? -

Verify repair Go to Step 17

Visually/Physically check the vacuum hoses for splits, kinks and

proper connections and proper connections and routing as

shown on the "Emission Control System Schematics".

Was a problem found? -

Verify repair Go to Step 18

18 Check the exhaust system for a possible restriction:

•Damaged or collapsed pipes

•Internal muffler failure -Verify repair Go to Step 19

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan Tool data.

•All electrical connections within a suspected circuit and/or

system.

Was a problem found?

Verify repair

Contact

Technical

Assistance

LACK OF POWER, SLUGGISH OR SPONGY SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Engine delivers less than expected power. Little or no increase in speed when accelerator pedal is pushed down

part-way.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

1. Remove and check the air filter element for dirt or

restrictions. Refer to Air Intake System in On-Vehicle

Service.

2. Replace the air filter element if necessary.

Was a repair required?

Verify repair Go to Step 5

5Check for proper ignition voltage output with the spark tester

(Use commercially available tool).

Was a problem found? -

Verify repair Go to Step 6

1. Remove the spark plugs and check for gas or oil fouling,

cracks, wear, improper gap, burned electrodes, heavy

deposits or improper heat range.

2. If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 7

7Check the fuel pressure. Refer to Fuel System Pressure Test.

Was a problem found? -

Verify repair Go to Step 8

STEP ACTION VALUE(S) YES NO

8Check for water or alcohol contaminated fuel.

Was a problem found? -Verify repair Go to Step 9

Check the ECM grounds to verify that they are clean and tight.

Refer to the ECM wiring diagrams in Electrical Diagnosis.

Was a problem found? -

Verify repair Go to Step 10

Check the exhaust system for a possible restriction:

•Damaged or collapsed pipes

•Internal muffler failure

Was a problem found?

Verify repair Go to Step 10

Check for the following engine mechanical problems:

•Low compression

•Leaking cylinder head gasket

•Worn or incorrect camshaft

•Loose timing belt

Was a problem found?

Verify repair Go to Step 12

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan Tool data.

•All electrical connections within a suspected circuit and/or

system.

Was a problem found?

Verify repair

Contact

Technical

Assistance

DETONATION/SPARK KNOCK SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with

throttle opening.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

1. If scan tool readings are normal (refer to Typical Scan

Values) and there are no engine mechanical faults, fill the

fuel tank with a known quality gasoline that has a minimum

octane rating Showing on the applicable specification list.

2. Re-evaluate the vehicle performance.

Is detonation present?

Go to Step 5 Verify Repair

1. Check for obvious overheating problems:

•Low engine coolant.

•Restricted air flow to radiator, or restricted water flow

through radiator.

•Incorrect coolant solution. It should be a 50/50 mix of

approved antifreeze/water.

2. If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 6

6Check fuel pressure. Refer to Fuel System Pressure Test.

Was a problem found? -Verify repair Go to Step 7

7Check items that can cause the engine to run lean.

Refer to Diagnostic Aids in Diagnostic Trouble Code 44 (If

applicable).

Was a problem found?

-Verify repair Go to Step 8

STEP ACTION VALUE(S) YES NO

8Check spark plugs for proper heat range. Refer to General

Information.

Were incorrect spark plugs installed? -

Verify repair Go to Step 9

1. Remove excessive carbon buildup with a top engine cleaner.

Refer to instructions on the top engine cleaner can.

2. Re-evaluate vehicle performance.

Is detonation still present? -

Go to Step 10 Verify repair

10 Check for an engine mechanical problem. Perform a cylinder

compression check. Refer to Engine Mechanical.

Was a problem found? -

Verify repair Go to Step 11

1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan tool data.

•All electrical connections within a suspected circuit and/or

system.

Was a problem found?

Verify repair

Contact

Technical

Assistance

ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING SYMPTOM (FOR OPEN LOOP SYSTEM)

STEP ACTION VALUE(S) YES NO

DEFINITION: Engine runs unevenly at idle. If severe, the engine or vehicle may shake. Engine idle speed may vary in RPM.

Either condition may be severe enough to stall the engine.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed, including the rotor,

ignition coil and secondary ignition wires? -

Go to Step 4

Go to

Visual/Physical

Check

1. Check for incorrect idle speed. Ensure that the following

conditions are present.

•Engine fully warm.

•Accessories are OFF.

2. Using a Scan Tool, monitor IAC position.

Is the IAC position within the specified values?

Between 8 and

50 counts

Go to Step 7 Go to Step 5

1. Visually/Physically inspect for the following conditions:

•Restricted air intake system. Check for a restricted air

filter element, or foreign objects blocking the air intake

system.

•Check for objects blocking the IAC passage or throttle

bore, excessive deposits in the IAC passage and on the

IAC pintle, and excessive deposits in the throttle bore and

on the throttle plate.

•Check for a condition that causes a large vacuum leak,

such as an incorrectly installed or faulty crankcase

ventilation hose/brake booster hose.

Was a problem found?

Verify repair Go to Step 6

Using a Scan Tool, monitor TP angle with the engine idling.

Is the TP angle at the specified value and steady?

0% Go to Step 7

Refer to

Diagnostic

Trouble Code

21 for further

diagnosis

7Check for proper ignition voltage output with the spark tester

(Use commercially available tool).

Was a problem found? -

Verify repair Go to Step 8

1. Remove the spark plugs and check for gas or oil fouling

cracks, wear, improper gap, burned electrodes, heavy

deposits or improper heat range

2. If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 9

STEP ACTION VALUE(S) YES NO

9Check for a lose ignition coil ground.

Refer to Electrical Ignition System.

Was a problem found? -

Verify repair Go to Step 10

10 Check the items that can cause the engine to run lean.

Refer to Idle CO Concentration Check and Adjustment.

Was a problem found?

Verify repair Go to Step 11

11 Check the injector connections, if any of the injectors are

connected an incorrect cylinder, correct as necessary.

Was a problem found? -

Verify repair Go to Step 12

12 Perform the injector Coil/Balance Test.

Was a problem found? -Verify repair Go to Step 13

Check the following engine mechanical problems:

Low compression

Leaking cylinder head gasket

Worn or incorrect camshaft

Sticking or leaking valves

Broken valve springs

Camshaft drive belt slipped or stripped

Was a problem found?

Verify repair Go to Step 14

1. Check for faulty motor mounts. Refer to Engine Mechanical

for inspection of mounts.

2. If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 15

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

Visual/ Physical inspection

Scan tool data

All electrical connections within a suspected circuit and/or

system

Was a problem found?

Verify repair

Contact

Technical

Assistance

ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING SYMPTON (FOR CLOSED LOOP SYSTEM)

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System Check”

performed? -

Go to Step 2

Go to OBD

System Check

1. Read the “Caution” above.

2. Relieve the fuel system pressure and install the fuel pump

pressure gauge to the test fitting.

3. Use a scan tool to command the fuel pump ON.

Is there an immediate pressure build-up which indicates the

pump is running?

Go to Step 3 Go to Step 4

1. Verify that the pump is not running by removi ng the fuel filler

cap and listening.

2. Command the pump ON with the scan tool.

Did the pump turn OFF after 2 seconds?

-Test

completed Go to Step 12

1. Ignition OFF.

2. Remove the fuel pump relay.

3. Using a test light connected to ground, probe the battery

feed to the relay.

Did the light illuminate?

Go to Step 6 Go to Step 5

5Repair short or open battery feed to fuel pump relay.

Is the action complete? -Verify repair -

1. Connect a test light between the two wires that connect to

the fuel pump relay pull-in coil.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off? -

Go to Step 12 Go to Step 7

1. With a test light connected to battery (-), probe the fuel

pump relay connector at the wire which runs from the relay

pull-in coil to the ECM.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off?

Go to Step 8 Go to Step 9

8Locate and repair open in the fuel pump relay ground circuit.

Is the action complete? -

Verify repair

Check for short or open between the ECM and the fuel pump

relay.

Was a problem found? -Verify repair Go to Step 10

1. Check the fuel pump relay circuit for a poor terminal

connection at the ECM.

2. If a problem is found, replace terminal as necessary.

Was a problem found?

Verify repair Go to Step 11

Replace the ECM.

Important: The replacement ECM must be programmed. Refer

to On-Vehicle Service in Powertrain Control Module and

Sensors for procedures.

Is the action complete?

Verify repair

STEP ACTION VALUE(S) YES NO

1. Reconnect the fuel pump relay.

2. Disconnect the fuel pump electrical connector at the fuel

tank.

3. Using a test light connected to ground, probe the fuel pump

feed wire (harness side).

4. Command the fuel pump ON with a scan tool.

Did the light illuminate for 2 seconds?

Go to Step 15 Go to Step 13

1. Honk the horn to verify that horn relay is functioning.

2. Susbstitute the horn relay for the fuel pump relay.

3. Leave the test light connected as in step 12.

4. Command the fuel pump ON with the scan tool.

Did the test light illuminate for 2 seconds when the fuel pump

was commanded ON?

Go to Step 17 Go to Step 14

1. Re-connect the horn relay in its proper location.

2. Check for a short circuit, blown fuse or open circuit between

the relay and the fuel tank.

Is the action complete?

Verify repair

1. with the fuel pump electrical connector at the fuel tank

disconnected, connect a test light between the feed wire and

the ground wire (harness side).

2. Command the fuel pump ON with a scan tool.

Did the test light illuminate for 2 seconds.

Go to Step 18 Go to Step 16

16 Repair the open circuit in the fuel pump ground wire.

Is the action complete? -Verify repair -

17 1. Re-connect the horn relay in its proper location.

2. Replace the fuel pump relay.

Is the action complete? -

Verify repair

18 Replace the fuel pump.

Is the action complete? -Verify repair -

IDLE CO CONCENTRATION CHECK AND

ADJUSTMENT

1. Before starting adjusting work, check and confirm the

following conditions.

Normal engine operating temperature.

All accessories switched off.

Throttle valve closed.

Transmission in neutral.

2. Before starting adjusting work, step on accelerator pedal

a few times and do racing up to 3000rpm.

3. After taking foot off accelerator pedal, short out pins #5 +

#6 of ALDL Connector(Fixed under center console panel)

short.

(When you do this, Check Engine Lamp will blink, and

engine rpm will rise to 100 to 1600rpm)

4. In this condition, connect CO meter with Tail Pig and

check CO value(%).

5. If CO value is within the range shown below, leave as it

is. If it is out of range, adjust I t by turning the screw of

CO Adjuster.

(After adjusting, confirm that CO value becomes stable.)

Note: After adjusting work is finished, apply the liquid gasket to

the CO adjuster screw. And after that, all conditions to

restore to former state.

Regulated range of CO concentration value:

1.0 +0.2

- 0.5

POOR FUEL ECONOMY SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, economy is noticeably

lower than it was on this vehicle at one time, as previously shown by an actual road test.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

Check owner's driving habits.

•Is the A/C On full time (defroster mode ON)?

•Are tires at the correct pressure?

•Are excessively heavy loads being carried?

•Is acceleration too much, too often?

Go to Step 5 Go to Step 6

5Review the items in Step 4 with the customer and advise as

necessary.

Is the action complete? -

System OK

1. Visually/Physically check: Vacuum hoses for splits, kinks,

and improper connections and routing as shown on the

"Emission Control System schematics".

Was a problem found?

Verify repair Go to Step 7

7Remove and check the air filter element for dirt or for

restrictions.

Was a problem found? -

Verify repair Go to Step 8

1. Remove the spark plugs and check for gas or oil fouling

cracks, wear, improper gap, burned electrodes of heavy

deposits.

2. Is spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 9

9Check for low engine coolant level.

Was a problem found? -Verify repair Go to Step 10

10 Check for an incorrect or faulty engine thermostat.

Refer to Engine Cooling.

Was a problem found? -

Verify repair Go to Step 11

11 Check for low engine compression. Refer to Engine Mechanical.

Was a problem found? -

Verify repair Go to Step 12

STEP ACTION VALUE(S) YES NO

12 Check for proper calibration of the speedometer.

Does the speed indicated on the speedometer closely match the

vehicle speed displayed on the Scan Tool? -

Go to Step 14 Go to Step 13

13 Diagnose and repair the inaccurate speedometer condition as

necessary. Refer to Vehicle Speed Sensor in Electrical

Diagnosis.-

Verify repair

14 Check the air intake system and the crankcase for air leaks.

Was a problem found? -

Verify repair Go to Step 15

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection

•Scan tool data

•All electrical connections within a suspected circuit and/or

system

Was a problem found?

Verify repair Go to Step 16

16 Perform the procedure in Fuel System Pressure Test .

Was the fuel pressure normal? - Contact

Technical

Assistance Verify repair

DIESELING, RUN-ON SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Engine continues to run after key is turned OFF, but runs very rough. If engine runs smoothly, check the ignition

switch and adjustment.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify repair Go to Step 3

3 Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

41. Check for a short between B+ and the ignition feed circuit.

Was a problem found? -

Verify repair Go to Step 5

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan Tool data.

•All electrical connections within a suspected circuit and/or

system.

Was a problem found?

Verify repair

Contact

Technical

Assistance

BACKFIRE SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

4Check for proper ignition voltage output with the spark tester

(Use commercially available tool).

Was a problem found? -

Verify repair Go to Step 5

1. Remove the spark plugs and check for gas or oil fouling

cracks, wear, improper gap, burned electrodes of heavy

deposits.

2. If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 6

1. Visually/Physically inspect the secondary ignition wires.

Check for the following conditions:

•Verify that all ignition wire resistance are less than the

specified value.

•Verify that ignition wires are correctly routed to eliminate

cross-firing.

•Verify that ignition wires are not arcing to ground. Spraying

the secondary ignition wires with a light mist of water may

help locate an intermittent problem.

Was a problem found?

Verify repair Go to Step 7

Check for an intermittent ignition system malfunction:

•Intermittent CKP 58X signal.

•Intermittent ignition feed circuit or sensor ground circuit to the

crankshaft position sensor.

Was a problem found?

Verify repair Go to Step 8

STEP ACTION VALUE(S) YES NO

8Refer to Fuel System Diagnosis to determine if there is a

problem with fuel delivery.

Was a problem found? -

Verify repair Go to Step 9

Check for the following engine mechanical problems:

•Low compression

•Leaking cylinder head gasket

•Worn or incorrect camshaft

•Incorrect valve timing

•Sticking or leaking valves

•Camshaft drive belt slipped or stripped.

Was a problem found?

Verify repair Go to Step 10

10 Check the intake and exhaust manifold(s) for casting flash.

Refer to Engine Mechanical.

Was a problem found? -

Verify repair Go to Step 11

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan Tool data.

•All electrical connections within a suspected circuit and/or

system.

Was a problem found?

Verify repair

Contact

Technical

Assistance

CUTS OUT, MISSES SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Steady pulsation or jerking that follows engine speed; usually more pronounced as engine load increases.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to Visual/

Physical

Check

Check the ECM grounds to verify that they are clean and tight.

Refer to the ECM wiring diagrams in Electrical Diagnosis.

Was a problem found? -

Verify repair Go to Step 5

5Monitor "02 Status" on the Scan Tool.

Is the "02 Status" in the rich condition (If applicable) ? Go to Step 6 Go to Step 7

6Check items that can cause the engine to run rich.

Refer to "Diagnostic Aids" in Diagnostic Trouble Code 45 (If

applicable).

Was a problem found?

Verify repair Go to Step 9

7 Is the "02 Status" significantly in the lean condition (If

applicable)? -Go to Step 8 Go to Step 9

8Check items that can cause the engine to run lean.

Refer to Diagnostic Aids in Diagnostic Trouble Code 44 (If

applicable).

Was a problem found?

Verify repair Go to Step 9

1. Check for incorrect idle speed. Ensure that the following

conditions are present:

•Engine fully warm.

•Accessories are OFF.

2. Using a Scan Tool, monitor the IAC position.

Is the IAC position within the specified values?

Between

5 and 50

counts Go to Step 11 Go to Step 10

1. Visually/Physically inspect for the following conditions:

•Restricted air intake system. Check for a restricted air

filter element, or foreign objects blocking the air intake

system.

•Check for objects blocking the IAC passage or throttle

bore, excessive deposits in the IAC passage and on the

IAC pintle, and excessive deposits in the throttle bore and

on the throttle plate.

•Check for a condition that causes a large vacuum leak,

such as an incorrectly installed or faulty crankcase

ventilation hoses or brake booster hose disconnected.

Was a problem found?

Verify repair Go to Step 11

STEP ACTION VALUE(S) YES NO

1. Check the injector connections. If any of the injectors are

connected to an incorrect cylinder, correct as necessary.

Was a problem found? -

Verify repair Go to Step 12

12 1. Perform the Injector Coil/Balance Test.

Was a problem found? -Verify repair Go to Step 13

1. Check for fuel in the pressure regulator vacuum hose.

2. If fuel is present, replace the fuel pressure regulator

assembly.

Was a problem found?

Verify repair Go to Step 14

14 Check for proper ignition voltage output with the spark tester

(Use commercially available tool).

Was a problem found? -

Verify repair Go to Step 15

1. Remove spark plugs and check for gas or oil fouling cracks,

wear, improper gap, burned electrodes of heavy deposits.

2. If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 16

16 Check for a loose ignition control module ground.

Was a problem found? -Verify repair Go to Step 17

Using a Scan Tool, monitor the TP angle with the engine idling.

Is the TP angle at the specified value and steady?

0% Go to Step 18

Refer to

Diagnostic

Trouble Code

21 for further

diagnosis

STEP ACTION VALUE(S) YES NO

18 Check the PCV passage for proper operation.

Was a problem found? -Verify repair Go to Step 19

Check the following engine mechanical problems:

•Low compression

•Leaking cylinder head gasket

•Worn or incorrect camshaft

•Sticking or leaking valves

•Valve timing

•Broken valve springs

•Camshaft drive belt slipped or stripped.

Was a problem found?

Verify repair Go to Step 20

20 Check for faulty motor mounts. Refer to Engine Mechanical for

inspection of mounts.

Was a problem found? -

Verify repair Go to Step 21

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan Tool data.

•All electrical connections within a suspected circuit and/or

system.

Was a problem found?

Verify repair

Contact

Technical

Assistance

HESITATION, SAG, STUMBLE SYMPTOM

STEP ACTION VALUE(S) YES NO

DEFINITION: Momentary lack of response as the accelerator is pushed down. Can occur at any vehicle speed.

Usually most pronounced when first trying to make the vehicle move, as from a stop sign. May cause the engine to stall if severe

enough.

1Was the On-Board Diagnostic (OBD) System Check performed? -

Go to Step 2

Go to OBD

System Check

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found, correct the

condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Verify Repair Go to Step 3

3Was a visual/physical check performed? -

Go to Step 4

Go to

Visual/Physical

Check

1. Check the fuel control heated oxygen sensor (If applicable).

The HO2S should respond quickly to different to throttle

positions. If it doesn't, check for silicon or other contaminants

from fuel or use of improper RTV sealant. The sensors may

have a white powdery coating. Silicon contamination sends a

rich exhaust signal which causes the ECM to command an

excessively lean air/fuel mixture.

Was a problem found?

Verify repair Go to Step 5

5Check the fuel pressure. Refer to Fuel System Pressure Test.

Was a problem found? -

Verify repair Go to Step 6

Observe the "TP angle" display on the Scan Tool while slowly

increasing throttle pedal.

Does the TP angle display steadily increase from 0% at closed

throttle to 100% at WOT?

Go to Step 7 Go to Step 13

7Monitor "Long Term Fuel Trim" on the Scan Tool.

Is the "Long Term Fuel Trim" in the negative range (rich

condition)? -

Go to Step 8 Go to Step 9

8Check items that can cause the engine to run rich.

Refer to Diagnostic Aids in Diagnostic Trouble Code 45 (If

applicable).

Was a problem found?

Verify repair Go to Step 10

9Check items that can cause the engine to run lean.

Refer to Diagnostic Aids in Diagnostic Trouble Code 44 (If

applicable).

Was a problem found?

Verify repair Go to Step 10

Check for proper ignition voltage output with spark tester (Use

commercially available tool). Refer to Electronic Ignition System

for the procedure.

Was a problem found?

Verify repair Go to Step 11

11 Check for a loose ignition control module ground.

Was a problem found? -Verify repair Go to Step 12

STEP ACTION VALUE(S) YES NO

Visually/Physically inspect the secondary ignition wires. Check

for the following conditions.

•Verify that all ignition wire resistance are less than the

specified value.

•Value that ignition wires are correctly routed to eliminate

cross-firing.

•Verify that ignition wires are not arcing to ground. Spraying

the secondary ignition wires with a light mist of water may

help locate an intermittent problem.

Was a problem found?

#1 cyl. 4.7kΩ

#2 cyl. 3.9kΩ

#3 cyl. 3.4kΩ

#4 cyl. 3.1kΩVerify repair Go to Step 14

13 Replace the TP sensor. - Verify repair -

14 1. Check the ignition coil secondary resistance.

2. Replace the coil if it is greater than the specified value.

Was a problem found? 2.5 kΩVerify repair Go to Step 15

1. Remove the spark plugs and check for gas or oil fouling

cracks, wear, improper gap, burned electrodes of heavy

deposits.

2. If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

Verify repair Go to Step 16

Check the ECM grounds to verify that they are clean and tight.

Refer to the ECM wiring diagrams in Electrical Diagnosis.

Was a problem found? -

Verify repair Go to Step 17

Visually/Physically check the vacuum hoses for splits, kinks and

proper connections and proper connections and routing as

shown on the "Emission Control System Schematics".

Was a problem found? -

Verify repair Go to Step 18

1. Review all the diagnostic procedures within this table.

2. If all procedures have been completed and no malfunctions

have been found, review/inspect the following:

•Visual/physical inspection.

•Scan Tool data.

•All electrical connections within a suspected circuit and/or

system.

3. If a problem is found, repair as necessary.

Was a problem found?

Verify repair

Contact

Technical

Assistance

DEFAULT MATRIX TABLE

SERVICE PROCEDURE DEFAULT STRATEG Y

A referral strategy has been established to assist the

technician with additional information when the cause

of the failure cannot be determined. If no problem is

found after performing diagnostics, then refer to the

default matrix table for further diagnostic information.

DEFAULT MATRIX TABLE

STRATEGY BASED

DIAGNOSTIC CHARTS INITIAL DIAGNOSIS DEFAULT SECTION(S)

On-Board Diagnostic (OBD)

System Check Vehicle does not enter diagnostics. Chassis Electrical

On-Board Diagnostic (OBD)

System Check Vehicle enters diagnostics and communicates with

the Scan Tool.

MIL is ON in diagnostics. Engine does not start and

run.

Ignition System Check

On-Board Diagnostic (OBD)

System Check Engine starts and runs, no ECM codes set. Customer

complains of vibration. -

ECM Power and Ground

Check On-Board Diagnostic (OBD) System Check. Chassis Electrical

ECM Power and Ground

Check On-Board Diagnostic (OBD) System Check. ECM

power and ground circuits OK. Data link voltage

incorrect.

Chassis Electrical

SYMPTOMS INITIAL DIAGNOSIS DEFAULT SECTION(S)

Intermittens 1. On-board diagnostic (OBD) system check.

2. Careful visual/physical inspections. Chassis Electrical

Hard Starts 1. OBD system check.

2. Sensors (ECT, MAP, TP); MAP output chart.

3. Fuel system electrical test, fuel system diagnosis.

4. Ignition system.

5. IAC system check.

Engine Mechanical, Ignition System

Check, Exhaust System Diagnosis

Surges and/or Chuggles 1. OBD system check.

2. Heated oxygen sensors (If applicable).

3. Fuel system diagnosis.

4. Ignition system.

Calibration ID "Broadcast Code"

/Service Bulletins, Ignition System

Check, Generator Output, Exhaust

System Diagnosis

STRATEGY BASED

DIAGNOSTIC CHARTS INITIAL DIAGNOSIS DEFAULT SECTION(S)

Lack of Power, Sluggish or

Spongy 1. OBD system check.

2. Fuel system diagnosis.

3. Ignition system.

Refer to Exhaust System in Engine

Exhaust, Calibration ID/Service

Bulletins

Detonation/Spark Knock 1. OBD system check.

2. Fuel system diagnosis.

3. Ignition system.

Cooling System, Ignition System

Check, Calibration ID/Service Bulletins

Hesitation, Sag, Stumble 1. OBD system check.

2. TP.

3. MAP output check.

4. Fuel system diagnosis.

5. Fuel injector and fuel injector balance test.

6. EVAP emission canister purge control solenoid

valve (If applicable).

7. Ignition system.

Generator Output Voltage (refer to

Chassis Electrical), Calibration

ID/Service Bulletins, Ignition System

Check

Cuts Out, Misses 1. OBD system check.

2. Cylinder balance test. Ignition System Check

STRATEGY BASED

DIAGNOSTIC CHARTS INITIAL DIAGNOSIS DEFAULT SECTION(S)

Rough, Unstable, or

Incorrect Idle, Stalling 1. OBD system check.

2. Fuel injector and fuel injector balance test.

3. EVAP emission canister purge control solenoid

valve check (If applicable).

4. Ignition system.

5. IAC operation.

MAP Output Check, Throttle Linkage,

IAC System Check, A/C Clutch Control

Circuit Diagnosis, Crankcase

Ventilation System, Calibration

ID/Service Bulletins, Generator Output

Voltage (refer to Chassis Electrical),

Exhaust Diagnosis

Poor Fuel Economy 1. OBD system check.

2. Careful visual/physical inspection.

3. Ignition system.

4. Cooling system.

Exhaust System (refer to Engine

Exhaust)

Engine Cranks But Will Not

Run 1. OBD system check. Fuel System Electrical Diagnosis, Fuel

System Diagnosis, Fuel Injector and

Fuel Injector Balance Test.

Excessive Exhaust

Emissions or Odors 1. OBD system check.

2. Emission test.

3. Cooling system.

4. Fuel system diagnosis.

5. Fuel injector and fuel injector balance test.

6. EVAP emission canister purge control solenoid

valve (If applicable).

7. Crankcase ventilation system.

8. Ignition system.

9. MAP output check.

Exhaust Diagnosis, Calibration

ID/Service Bulletins

Dieseling, Run-On 1. OBD system check.

2. Careful visual/physical inspection.

3. Fuel system diagnosis.

Backfire 1. OBD system check.

2. Ignition system.

3. Fuel system diagnosis.

4. Fuel injector and fuel injector balance test.

Exhaust System Diagnosis, Intake

Casting Flash, Ignition System Check

Misfire 1. OBD system check.

2. Ignition system.

3. Fuel system diagnosis.

4. Fuel injector and fuel injector balance test.

Vibrations, Transmission, Driveshaft

and Axle

Catalyst Monitor 1. OBD system check.

2. Careful visual/physical inspection.

3. Heated oxygen sensors. (If applicable)

Exhaust System

Fuel Trim 1. OBD system check.

2. Careful visual/physical inspection.

3. Fuel system diagnosis.

4. Heated oxygen sensors. (If applicable)

Exhaust System Intake Air System

Evaporative Emissions

(If applicable) 1. OBD system check.

2. Careful visual/physical inspection.

3. Fuel system diagnosis. -

Heated Oxygen Sensors

(If applicable) 1. OBD system check.

2. Careful visual/physical inspection. Exhaust System

ENGINE CRANKS BUT WILL NOT RUN

CIRCUIT DESCRIPTION

The electronic ignition system uses a dual coil method

of spark distribution. In this type of ignition system, the

engine control module (ECM) triggers the correct

driver inside the ECM, which then triggers the correct

ignition timing based on the 58X signal received from

the crankshaft position sensor (CKP). The spark plug

connected to the coil fires when the coildriver opens

the ground circuit for the coil's primary circuit.

During crank, the ECM monitors the CKP 58X signal.

The CKP signal is used to determine which cylinder

will fire first. After the CKP 58X signal has been

processed by the ECM, the four injectors are divided

into two groups, one is composed of #1 and #4

cylinders, the other group, #2 and #3 cylinders.

58X signal is processed by ECM and it issues the

following command to each group at every turn of the

crankshaft.

To jet a half amount of the fuel required for a single

combustion stroke to each cylinder.

DIAGNOSTIC AIDS

An intermittent problem may be caused by a poor

connection, rubbed-through wire insulation or a wire

broken inside the insulation. Check for the following

items:

• Poor connection or damaged harness - Inspect the

ECM harness and connectors for improper mating,

broken locks, improperly formed or damaged

terminals, poor terminal-to-wire connection, and

damaged harness.

• Faulty engine coolant temperature sensor - Using a

scan tool, compare engine coolant temperature with

intake air temperature on a completely cool engine.

Engine coolant temperature should be within 10°C

of intake air temperature. If not, replace the ECT

sensor.

ENGINE CRANKS BUT WILL NOT RUN

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

2Use the Scan Tool and check for any DTC's.

Are any DTC's stored? - Go to

Applicable

DTC Table Go to Step 3

3Check the 15A ignition coil fuse, the 15A engine device fuse,

and the 15A ECM fuse.

Was a fuse blown? -

Go to Step 4 Go to Step 5

4Check for a short to ground and replace the fuse.

Is the action complete? -Verify repair -

1. Ignition ON

2. Use a grounded test lamp to verify that B+ is available at the

ignition coil fuse, the engine device fuse, and the ECM fuse.

3. Was B+ available at the fuses?

Go to Step 7 Go to Step 6

Repair the open ignition feed circuit.

Go to

Fuel System

Electrical Test

Go to

Fuel System

Diagnosis

STEP ACTION VALUE(S) YES NO

1. Disconnect the ignition secondary wire at the No.1.

2. Install a spark tester (Use commercially available tool) at the

end of the disconnected ignition coil.

3. Clip the spark tester (Use commercially available tool) to a

good ground (not near the battery).

4. Observe the spark tester while the engine is cranking.

Was a crisp blue spark observed? (Only one or two sparks

followed by no result is considered the same as “No Spark." )

Go to Step 16 Go to Step 8

1. Disconnect the ignition coil harness connector.

2. Check for an open or short circuit between the ignition coil

and the ECM?

Was a problem found?

Go to Step 9 Go to Step 10

9 Repair the faulty circuit. - Verify repair -

1. Ignition ON.

2. Using a Digital Voltmeter (DVM) check the ignition wire coil

at the ignition coil harness connector?

Was the voltage equal to the specified value?

B+

Go to Step 12 Go to Step 11

11 Repair the open circuit. - Verify repair -

1. Ignition OFF.

2. With DVM, check for an open in the ground wire at the

ignition coil harness connector.

Was the ground wire OK?

Go to Step 14 Go to Step 13

13 Repair the faulty wire. - Verify Repair -

14 Replace the ignition coil, verify the repair.

Attempt to start the engine.

Is there still a problem? -

Go to Step 15 Verify repair

15 Replace the EPROM or ECM. - Verify repair -

Use an ohmmeter to check the ignition coil primary winding

resistance.

Was the primary winding resistance approximately equal to the

specified value? 0.8-18ΩGo to Step 17 Go to Step 18

Use an ohmmeter to check the ignition coil secondary winding

resistance.

Was the secondary winding resistance hear arround the to the

specified value? 2.5kΩGo to Step 19 Go to Step 18

18 Replace the ignition coil. - Verify repair -

Test the resistance of the coil-to-spark plug secondary ignition

wire.

Was the resistance greater than the specified value?

#1 cyl. 4.7kΩ

#2 cyl. 3.9kΩ

#3 cyl. 3.4kΩ

#4 cyl. 3.1kΩGo to Step 20 Go to Step 21

Replace the coil-to-spark plug secondary ignition wire and any

other secondary wi res which exceed the specified value.

Is there still a problem?

#1 cyl. 4.7kΩ

#2 cyl. 3.9kΩ

#3 cyl. 3.4kΩ

#4 cyl. 3.1kΩGo to Step 21 Verify repair

STEP ACTION VALUE(S) YES NO

1. Remove the spark plugs from all cylinders.

2. Visually inspect the spark plug electrodes.

3. Replace any spark plugs with loose or missing electrodes or

cracked insulators.

Did your inspection reveal any spark plugs exhibiting excessing

fouling?

Correct the

fouling

condition Go to Step 33

22 Verify repair.

Attempt to start the engine.

Is there still a problem? -Go to Step 23 Go to Step 22

1. Ignition OFF install a fuel pressure gauge at the test fitting

on the fuel supply line in the engine compartment.

Caution: Use a shop cloth to absorb any fuel leakage while

making the connection.

2. Check the engine and observe the fuel pressure.

Is the fuel pressure within the specified values, and does it hold

steady for 2 seconds? 285-375 kPa

(43-55 psi)

Go to Step 25 Go to Step 24

Is any fuel pressure indicated?

Go to Fuel

System

Electrical Test

Go to Fuel

System

Diagnosis

1. Install switch box Injector Adaptor Cable 5-8840-2589-0 and

Fuel Injector Tester 5-8840-2618-0 to the injector connector.

2. Activate an injector.

Did the fuel pressure drop when the injector was activated? -

Go to Step 26

Go to Fuel

System

Diagnosis

Pressurize the fuel system using the ignition ON and switch the

injector connector to test pressure drop for each injector.

Was there a pressure drop when each injector was activated? -

Go to Step 27

Go to Fuel

System

Diagnosis

1. Remove all SST and re-assemble the all connectors and fuel

hoses to original position.

2. Crank the engine.

Does the engine start smoothly?

Go to Step 33 Go to Step 28

1. Raise the vehicle and disconnect the CKP sensor harness.

2. Ignition ON.

3. With a test light to ground, probe the CKP ignition feed

harness terminal.

Did the light illuminate?

Go to Step 29 Go to Step 30

1. Ignition ON.

2. At the CKP harness connector, connect a test lamp between

the ignition and ground terminals.

Did the lamp illuminate?

Go to Step 31 Go to Step 32

STEP ACTION VALUE(S) YES NO

30 Check the CKP High circuit between the sensor and the ECM

for a short to ground or open circuit.

Was a problem found? -

Verify Repair Go to Step 33

31 Replace the CKP position sensor.

Is there still a problem? -Go to Step 34 -

32 Check the CKP Low circuit between the sensor and the ECM

for: an open circuit, a short to ground, or short to voltage. Was

the problem found? -

Verify Repair Go to Step 33

33 Replace the EPROM or ECM. Note) Refer to 6E-243 - Verify Repair -

1. Test the fuel for contamination.

2. If a problem is found, clean the fuel system and correct the

contaminated fuel condition as necessary. Replace the fuel

filter and replace any injectors that are not delivering fuel

(see Injector Balance Test).

Was a problem found?

Verify repair Go to Step 35

Refer to Engine Mechanical Diagnosis to diagnose the following

conditions:

•Slipped camshaft drive belt.

•Leaking or sticky valves or rings.

•Excessive valve deposits.

•Loose or worn rocker arms.

•Weak valve springs.

•Leaking head gasket.

Is the action complete?

Verify repair

FUEL SYSTEM ELECTRICAL TEST

A13

Fuel

Injectors

Battery Joint Cable

ECM

Fuse

15A

1.25

R/W

1.25

R/W

A4 A5

Engine

Fuse

15A

Canister Purge

Control Solenoid Valve

E16

Engine

Control

Module

(ECM)

Fuel

Pump

Relay

Fuel Pump Fuse

20A

0.5

P/W

0.85

B/Y

CIRCUIT DESCRIPTION

When the ignition switch is first turned ON, the engine

control module (ECM) energizes the fuel pump relay

which applies power to the in-tank fuel pump. The fuel

pump relay will remain ON as long as the engine is

running or cranking and the ECM is receiving 58X

crankshaft position pulses. If no 58X crankshaft

position pulses are present, the ECM de-energizes the

fuel pump relay within 2 seconds after the ignition is

turned ON or the engine is stopped.

The fuel pump delivers fuel to the fuel rail and

injectors, then to the fuel pressure regulator. The fuel

pressure regulator controls fuel pressure by allowing

excess fuel to be returned to the fuel tank. With the

engine stopped and ignition ON, the fuel pump can be

turned ON by using a command by the scan tool.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection,

rubbed-through wire insulation, or a wire broken inside

the insulation. Check for the following items:

•Poor connection or damaged harness - Inspect the

ECM harness and connectors for improper mating,

broken locks, improperly formed or damaged

terminals, poor terminal-to-wire connection, and

damaged harness.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. If the fuel pump is operating but incorrect pressure

is noted, the fuel pump wiring is OK and the “Fuel

System Pressure Test” chart should be used for

diagnosis.

Caution: To reduce the risk of fire and

personal injury:

• It is necessary to relieve fuel system

pressure before connecting a fuel pressure

gauge. Refer to Fuel Pressure Relief

Procedure, below.

• A small amount of fuel may be released

when disconnecting the fuel lines. Cover

fuel line fittings with a shop towel before

disconnecting, to catch any fuel that may

leak out. Place the towel in an approved

container when the disconnect is

completed.

FUEL PRESSURE RELIEF PROCEDURE

1. Remove the fuel cap.

2. Remove the fuel pump relay from the underhood

relay center.

3. Start the engine and alow it to stall.

4. Crank the engine for an additional 3 seconds.

FUEL PRESSURE GAUGE INSTALLATION

1. Remove the shoulder fitting cap.

2. Install fuel pressure gauge 5-8840-0378-0 to the

fuel feed line located in front of and above the right

side valve cover.

3. Reinstall the fuel pump relay.

FUEL SYSTEM ELECTRICAL TEST

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

1. Turn Ignition “ON”.

2. Install Scan Tool

3. Command Fuel Pump “ON”.

Did the Fuel Pump turn on?

-Go to Fuel

System

Diagnosis Go to Step 3

1. Ignition OFF.

2. Remove the fuel pump relay.

3. Using a test light connected to ground, probe the battery

feed to the relay.

Did the light illuminate?

Go to Step 5 Go to Step 4

4Repair short or open battery feed to fuel pump relay.

Is the action complete? -Verify repair -

1. Connect a test light between the two wires that connect to

the fuel pump relay pull-in coil.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off? -

Go to Step 11 Go to Step 6

1. With a test light connected to battery (−), probe the fuel

pump relay connector at the wire which runs form the relay

pull-in coil to the ECM.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off?

Go to Step 7 Go to Step 8

STEP ACTION VALUE(S) YES NO

7Locate and repair open in the fuel pump relay ground circuit. Is

the action complete? -Verify repair -

8Check for short or open between the ECM and the fuel pump

relay.

Was a problem found?

Verify repair Go to Step 9

1. Check the fuel pump relay circuit for a poor terminal

connection at the ECM.

2. If a problem is found, replace terminal as necessary.

Was a problem found?

Verify repair Go to Step 10

10 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

1. Reconnect the fuel pump relay.

2. Disconnect the fuel pump electrical connector at the fuel

tank

3. Using a test light connected to ground, probe the fuel pump

feed wire (harness side).

4. Command the fuel pump ON with a scan tool.

Did the light illuminate for 2 seconds?

Go to Step 14 Go to Step 12

1. Honk the horn to verify that the horn relay is functioning.

2. Substitute the horn relay for the fuel pump relay.

3. Leave the test light connected as in step 12.

4. Command the fuel pump ON with the scan tool.

Did the test light illuminate for 2 seconds when the fuel pump

was commanded ON?

Go to Step 16 Go to Step 13

1. Re-connect the horn relay in its proper location.

2. Check for a short circuit, blown fuse or open circuit between

the relay and the fuel tank.

Is the action complete?

Verify repair

1. With the fuel pump electrical connector at the fuel tank

disconnected, connect a test light between the feed wire and

the ground wire (harness side).

2. Command the fuel pump ON with a scan tool.

Did the test light illuminate for 2 seconds?

Go to Step 17 Go to Step 15

15 Repair the open circuit in the fuel pump ground wire.

Is the action complete? -Verify repair -

16 1. Re-connect the horn relay in its proper location.

2. Replace the fuel pump relay.

Is the action complete? -

Verify repair

17 Replace the fuel pump.

Is the action complete? -Verify repair -

FUEL SYSTEM DIAGNOSIS

A13

Fuel

Injectors

Battery Joint Cable

ECM

Fuse

15A

1.25

R/W

1.25

R/W

A4 A5

Engine

Fuse

15A

Canister Purge

Control Solenoid Valve

E16

Engine

Control

Module

(ECM)

Fuel

Pump

Relay

Fuel Pump Fuse

20A

0.5

P/W

0.85

B/Y

CIRCUIT DESCRIPTION

When the ignition switch is turned ON, the engine

control module (ECM) will turn ON the in-tank fuel

pump. The in-tank fuel pump will remain ON as long

as the engine is cranking or running and the ECM is

receiving 58X crankshaft position pulses. If there are

no 58X crankshaft position pulses, the ECM will turn

the in-tank fuel pump OFF 2 seconds after the

ignition switch is turned ON or 2 seconds after the

engine stops running.

The in-tank fuel pump is an electric pump within an

integral reservoir. The in-tank fuel pump supplies fuel

through an in-line fuel filter to the fuel rail assembly.

The fuel pump is designed to provide fuel at a

pressure above the pressure needed by the fuel

injectors. A fuel pressure regulator, attached to the

fuel rail, keeps the fuel available to the fuel injectors

at a regulated pressure. Unused fuel is returned to

the fuel tank by a separate fuel return line.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. Connect the fuel pressure gauge to the fuel feed

line as shown in the f uel system illustration. W rap

a shop towel around the fuel pressure connection

in order to absorb any duel leakage that may

occur when installing the fuel pressure gauge.

With the ignition switch ON and the fuel pump

running, the fuel pressure indicated by the fuel

pressure gauge should be 283-376 kPa (41-55

psi). This pressure is controlled by the amount of

pressure the spring inside the fuel pressure

regulator can provide.

3. A f uel system that cannot m aintain a c onstant f uel

pressure has a leak in one or more of the

following areas:

•The fuel pump check valve.

•The fuel pump flex line.

•The valve or valve seat within the f uel pressure

regulator.

•The fuel injector(s).

4. Fuel pressure that drops off during acceleration,

cruise, or hard cornering may case a lean

condition. A lean condition can cause a loss of

power, surging, or m is fire. A lean c ondition c an be

diagnosed using a Tech 2 Scan Tool.

Following are applicable to the vehicle with

closed Loop System:

If an extremely lean condition occurs, the oxygen

sensor(s) will stop toggling. The oxygen sensor

output voltage(s) will drop below 500 mV. Also,

the fuel injector pulse width will increase.

Important: Make sure the fuel system is not

operating in the “Fuel Cut-Off Mode."

W hen the engine is at idle, the manifold pressure

is low (high vacuum). This low pressure (high

vacuum) is applied to the fuel pressure regulator

diaphragm. The low pressure (high vacuum) will

offset the pressure being applied to the fuel

pressure regulator diaphragm by the spring inside

the fuel pressure regulator. When this happens,

the result is lower f uel press ure. T he fuel pr essur e

at idle will vary slightly as the barom etric pressure

changes, but the fuel pressure at idle should

always be less than the fuel pressure noted in

step 2 with the engine OFF.

16.Check the spark plug associated with a particular

fuel injector for fouling or saturation in order to

determine if that particular fuel injector is leaking.

If checking the spark plug associated with a

particular fuel injector for fouling or saturation

does not determine that a particular f uel injector is

leaking, use the following procedure:

•Remove the fuel rail, but leave the fuel lines

and injectors c onnected to the fuel rail. Ref er to

Fuel Rail Assembly in On-Vehicle Service.

•Lift the fuel rail just enough to leave the fuel

injector nozzles in the fuel injector ports.

Caution: In order to reduce the risk of fire an d

personal injury that may result from fuel

spraying on the engi ne, verify that the fu el rail

is positioned over the fuel injector ports and

verify that the fuel injector retaining clips are

intact.

•

••

•Pressurize the fuel system by connecting a

20 amp fused jumper between B+ and the

fuel pump relay connector.

•

••

•Visually and physically inspect the fuel

injector nozzles for leaks.

17.A rich condition may result from the fuel pressure

being above 376 kPa (55 psi). A rich condition

may cause a 45 to set. Driveability conditions

associated with rich conditions can include hard

starting (followed by black smoke) and a strong

sulfur smell in the exhaust.

20.This test determines if the high fuel pressure is

due to a restricted fuel r eturn line or if the high f uel

pressure is due to a faulty fuel pressure regulator.

21.A lean condition may result from fuel pressure

below 333 kPa (48 psi). A lean condition may

cause a 44 to set. Driveability conditions

associated with lean conditions can include hard

starting (when the engine is c old), hesitation, poor

driveability, lack of power, surging, and misfiring.

22.Restricting the fuel return line causes the fuel

pressure to rise above the regulated fuel pressure.

Command the fuel pump ON with the scan tool.

The fuel pressure should rise above 376 kPa (55

psi) as the fuel return line becomes partially

closed.

Notice: Do not allow the fuel pressure to exceed 414

kPa (60 psi). Fuel pressure in excess of 414 kPa (60

psi) may damage the fuel pressure regulator.

Caution: To reduce the risk of fire and

personal injury:

•It is necessary to relieve fuel system

pressure before connecting a fuel pressure

gauge. Refer to Fuel Pressure Relief

Procedure, below.

•A small amount of fuel may be released

when disconnecting the fuel lines. Cover

fuel line fittings with a shop towel before

disconnecting, to catch any fuel that may

leak out. Place the towel in an approved

container when the disconnect is

completed.

FUEL PRESSURE RELIEF PROCEDURE

1. Remove the fuel cap.

2. Located on the intake manifold which is at the top

right part of the engine.

3. Start the engine and allow it to stall.

4. Crank the engine for an additional 3 seconds.

FUEL PRESSURE GAUGE INSTALLATION

1. Remove the shoulder fitting cap.

2. Install fuel pressure gauge 5-8840-0378-0 to the

fuel feed line located on the upper right side of the

engine.

3. Reinstall the fuel pump relay.

FUEL SYSTEM DIAGNOSIS

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

1. Turn the ignition OFF.

2. Turn the air conditioning system OFF.

3. Relieve fuel system pressure and install the fuel pressure

gauge.

4. Turn the ignition ON.

Note: The fuel pump will run for approximately 2 seconds. Use

the Scan Tool to command the fuel pump ON.

5. Observe the fuel pressure indicated by the fuel pressure

gauge with the fuel pump running.

Is the fuel pressure within the specified limits? 283-376 kPa

(41-55 psi) Go to Step 3 Go to Step 17

Does the fuel pressure indicated by the fuel pressure gauge

remain constant?

Note: The fuel pressure will drop when the fuel pump stops

running, then it should stabilize and remain constant.

Go to Step 4 Go to Step 12

1. When the vehicle is at normal operating temperature, turn

the ignition ON to build fuel pressure and observe the

measurement on the gauge.

2. Start the engine and observe the fuel pressure gauge.

Did the reading drop by the amount specified after the engine

was started? 21-105 kPa

(3-15 psi) Go to Step 5 Go to Step 9

5Is fuel pressure dropping off during acceleration, cruise, or hard

cornering? -

Go to Step 6

Check for

improper fuel

Visually and physically inspect the following items for a

restriction:

•The in-pipe fuel filter.

•The fuel feed line.

Was a restriction found?

Verify repair Go to Step 7

Remove the fuel tank and visually and physically inspect the

following items:

•The fuel pump strainer for a restriction.

•The fuel line for a leak.

•Verify that the correct fuel pump is in the vehicle.

Was a problem found in any of these areas?

Verify repair Go to Step 8

STEP ACTION VALUE(S) YES NO

8Replace the fuel pump.

Is the action complete? -Verify repair -

1. Disconnect the vacuum hose from the fuel pressure

regulator.

2. With the engine idling, apply 12-14 inches of vacuum to the

fuel pressure regulator.

Does the fuel pressure indicated by the fuel pressure gauge

drop by the amount specified? 21-105 kPa

(3-15 psi) Go to Step 10 Go to Step 11

10 Locate and repair the loss of vacuum to the fuel pressure

regulator.

Is the action complete? -

Verify repair

11 Replace the fuel pressure regulator.

Is the action complete? -Verify repair -

1. Run the fuel pump with the Scan Tool.

2. After pressure has built up, turn off the pump and clamp the

supply hose shut with suitable locking pliers.

Does the fuel pressure indicated by the fuel pressure gauge

remain constant?

Go to Step 13 Go to Step 15

13 Visually inspect the fuel supply line and repair any leaks.

Was a problem found? -Verify repair

Go to STep 14

14 Remove the fuel tank and inspect for leaky hose or in-tank fuel

line.

Was a problem found? -

Verify repair Go to STep 8

1. If the pliers are still clamped to the fuel supply hose, remove

the locking pliers.

2. With suitable locking pliers, clamp the fuel return line to

prevent fuel from returning to the fuel tank.

3. Run the fuel pump with the Scan Tool.

4. After pressure has built up, remove power to the pump.

Does the fuel pressure indicated by the fuel pressure gauge

remain constant?

Go to Step 11 Go to Step 16

16 Locate and replace any leaking fuel injector(s).

Is the action complete? -Verify repair -

17 Is the fuel pressure indicated by the fuel pressure gauge above

the specified limit? 376 kPa

(55 psi) Go to Step 18 Go to Step 21

1. Relieve the fuel pressure. Refer to the Fuel Pressure Relief.

2. Disconnect the fuel return line from the fuel rail.

3. Attach a length of flexible hose to the fuel rail return outlet

passage.

4. Place the open end of the flexible hose into an approved

gasoline container.

5. Run the fuel pump with the Scan Tool.

6. Observe the fuel pressure indicated by the fuel pressure

gauge with the fuel pump running.

Is the fuel pressure within the specified limits? 290-376 kPa

(42-55 psi) Go to Step 19 Go to Step 20

STEP ACTION VALUE(S) YES NO

19 Locate and correct the restriction in the fuel return line.

Is the action complete? -Verify repair -

20 Visually and physically inspect the fuel rail outlet passages for a

restriction.

Was a restriction found? -

Verify repair Go to Step 11

21 Is the fuel pressure indicated by the fuel pressure gauge above

the specified value? 0 kPa (0 psi) Go to Step 22 Go to Step 23

1. Command the fuel pump ON with the Scan Tool.

2. Using suitable pliers which will not damage the fuel hose,

gradually apply pressure with the pliers to pinch the flexible

fuel return hose closed.

Does the fuel pressure indicated by the fuel pressure gauge rise

above the first specified value?

Caution: Do not let the fuel pressure exceed the second

specified value.

376 kPa

(55 psi)

414 kPa

(60 psi) Go to Step 11 Go to Step 7

1. Command the fuel pump ON with the Scan Tool.

2. Remove the fuel filler cap and listen for the sound of the fuel

pump running.

3. Turn the pump off.

Was the fuel pump running?

Go to Step 7

Go to

Fuel System

Electrical Test

Chart

MANIFOLD ABSOLUTE PRESSURE (MAP) OUTPUT CHECK

0.5

YEL/

GRN

0.5

GRN

0.5

RED

0.5

RED

0.5

GRN

0.5

RED

Manifold

Absolute

Pressure

(MAP)

Sensor

F10 B2

0.5

GRN

B7 A3

5 Volt

Reference

Signal

MAP Sensor

Input

Sensor

Ground

0.75

AB C

Intake

Air Temperature

Sensor

Throttle Position

Sensor

Engine

Control

Module

(ECM)

HI OUT LO

0.5

CIRCUIT DESCRIPTION

The manifold absolute pressure (MAP) sensor

measures the changes in the intake MAP which result

from engine load (intake manifold vacuum) and engine

speed changes; and converts these into a voltage

output. The engine control module (ECM) sends a 5-

volt reference voltage to the MAP sensor. As the MAP

changes, the output voltage of the sensor also

changes. By monitoring the sensor output voltage, the

ECM knows the MAP. A lower pressure (low voltage)

output voltage will be about 1-2 volts at idle. Higher

pressure (high voltage) output voltage will be about 4-

4.8 volts at wide open throttle. The MAP sensor is also

used, under certain conditions, to measure barometric

pressure, allowing the ECM to make adjustments for

different altitudes.

TEST DESCRIPTION

Important: Be sure to use the same diagnostic test

equipment for all measurements.

The number(s) below refer to the step number(s) on

the Diagnostic Chart.

1. When you compare the Scan Tool readings to a

known good vehicle, it is important to compare

vehicles that use MAP s ensors that have the sam e

part number.

2. Applying 34 kPa (10 Hg) vacuum to the MAP

sensor s hould cause the voltage to be 1.5- 2.1 volts

less than the voltage at step 1. Upon applying

vacuum to the sensor, the change in voltage

should be instantaneous. A slow voltage change

indicates a faulty sensor.

3. Check the vacuum hose to the sensor for leaking

or restriction. Be sure that no other vacuum

devices are connected to the MAP hose.

Important: Make sure the electrical connector

remains securely fastened.

4. Disconnect the sensor from the bracket. Twist the

sensor with your hand to check for an intermittent

connection. Output changes greater than 0.10 volt

indicate a bad sensor.

MANIFOLD ABSOLUTE PRESSURE (MAP) O UTPUT CHECK

STEP ACTION VALUE(S) YES NO

1. Turn the ignition OFF and leave it OFF for 15 seconds.

2. Ignition ON. Do not crank engine.

3. The Scan Tool should indicate a manifold absolute pressure

(MAP) sensor voltage.

4. Compare this scan reading to the scan reading of a known

good vehicle obtained using the exact same procedure as in

Steps 1-4.

Is the voltage reading the same +/−0.40 volt?

Go to Step 2 Go to Step 5

1. Disconnect the MAP sensor and plug the hole on the intake

manifold.

2. Using an adequate rubber hose, connect a hand vacuum

pump to the MAP sensor.

3. Check for the following condition:

•MAP port sealing rubber damaged or split?

•Intake vacuum leaks at;

•Vacuum leaks at throttle body;

If a problem is found, repair as necessary.

Was a problem found?

4. Start the engine.

5. Apply 34 kPa (10 Hg) of vacuum and note the voltage

change.

Is the voltage change 1.5-2.1 volts less than step 1?

Go to Step 3 Go to Step 4

3No trouble found. Check the sensor seal rubber (color : orange)

for leakage or restriction.

Does the hose supply vacuum to the MAP sensor only? -

Go to Step 5 Go to Step 4

4Repair the seal rubber (color : orange) to ensure the hose

supplies vacuum to the MAP sensor only

Is the action complete? -

Verify repair

5Check the sensor connection.

Is the sensor connection good? -Go to Step 6 Go to Step 7

6Replace the sensor. Refer to On-Vehicle Service, MAP Sensor.

Is the action complete? -

Verify repair

7Repair the poor connection.

Is the action complete? -Verify repair -

EVAPORATIVE EMISSIONS (EVAP) CANISTER PURGE CONTROL

SOLENOID VALVE CHECK (IF APPLICABLE)

CIRCUIT DESCRIPTION

Canister purge is controlled by a solenoid valve that

allows manifold vacuum to purge the canister. The

engine control module (ECM) supplies a ground to

energize the solenoid valve (purge ON). The EVAP

(purge solenoid control is turned ON time) is

determined by engine operating conditions including

load, throttle position, coolant temperature and

ambient temperature. The duty cycle is calculated by

the ECM and the purge solenoid is enabled when the

appropriate conditions have been met:

•The engine run time after start is more than 60

seconds.

•The engine coolant temperature is above 30°C

(86°F).

•The fuel control system is operating in the “Closed-

Loop” mode (If applicable).

DIAGNOSTIC AIDS

•Make a visual check of vacuum hoses.

•Check the throttle body for possible cracked or

plugged vacuum block.

•Check the malfunc tion indicator lamp for a possible

mechanical problem.

TEST DESCRIPTION

The number(s) below refer to the step number(s) on

the Diagnostic Chart.

1. Check to see if the solenoid is open or closed. The

solenoid is normally de-energized in this step, so it

should be closed.

2. This step checks to determine if the solenoid was

open due to an electrical circuit problem or a

defective solenoid.

3. This should normally energize the solenoid,

opening the valve and allowing the vacuum to dr op

(Purge ON).

EVAPORATIVE EMISSIO NS ( EVAP) CANISTER PURGE VALVE SOLENOID CHECK

STEP ACTION VALUE(S) YES NO

1. Ignition OFF.

2. Ignition ON, engine OFF.

3. At the intake manifold, disconnect the hose that goes to the

pump solenoid.

4. Using a hand vacuum purge with an attached vacuum gauge

5-8840-0279-0, apply vacuum (10” Hg or 34 kPa) to the

solenoid.

Does the solenoid hold vacuum?

Go to Step 3 Go to Step 2

1. Disconnect the solenoid electrical connector.

2. As in Step 1, apply vacuum (10” Hg or 34 kPa) to the

solenoid.

Does the solenoid hold vacuum?

Go to Step 4 Go to Step 7

1. At the intake manifold, put a cap over the vacuum port where

the hose was disconnected for testing.

This is to prevent a vacuum leak when the engine is started.

2. Ignition OFF.

3. Install the scan tool.

4. Apply vacuum to the purge control solenoid with the hand

vacuum pump.

5. Start the engine, run at 2500 RPM.

6. Using the Scan Tool command the purge control solenoid

ON.

Did the vacuum drop when the purge was turned on?

Go to Step 8 Go to Step 9

4Check for a short to ground or open in the wire between the

solenoid and the ECM.

Is there a problem? -

Go to Step 5 Go to Step 6

5Repair the faulty wire.

Is the action complete? -Verify repair -

6 Replace the EPROM or ECM.Note) Refer to 6E1-243. - Verify repair -

7Replace the faulty purge control solenoid. Refer to On-Vehicle

Service, EVAP Canister Purge Solenoid.

Is the action complete? -.

Verify repair

1. Turn the ignition OFF.

2. Verify the purge hose nipple is not plugged.

No problem

found in the

EVAP

emission

canister purge

valve check.

Refer to

Diagnostic

Aids

1. Turn the Ignition OFF.

2. Disconnect the solenoid's electrical connector.

3. Connect a test lamp between the harness terminals.

4. Turn the ignition ON.

Does the test lamp light?

Go to Step 7 Go to Step 10

STEP ACTION VALUE(S) YES NO

10 Probe each terminal of the solenoid valve electrical connector

with a test lamp to ground.

Does the test lamp light on both terminals? -

Go to Step 11 Go to Step 12

11 Repair the short to voltage in the wire between the solenoid and

the ECM.

Is the action complete? -

Verify repair

12 Does the ignition feed terminals light the test lamp? - Go to Step 13 Go to Step 14

13 Check for an open in the wire between the purge control

solenoid and the ECM.

Was there an open circuit? -

Go to Step 15 Go to Step 6

14 Repair the open in the ignition feed wire.

Is the action complete? -Verify repair -

15 Repair the open wire.

Is the action complete? -Verify repair -

THROTTLE POSITION (TP) SENSOR CI RCUIT RANGE/ PERFORMANCE

PROBLEM

0.5

RED

0.75

GRN

0.75

0.5

GRN

Engine

Control

Module

(ECM)

F14 B1 A3

5 Volt

Reference

Signal

Throttle

Position

(TP)

Sensor

Input

Sensor

Ground

Sensor

Ground

B7 B2

Throttle

Position

(TP)

Sensor

B C A

Manifold

Absolute

Pressure

Sensor

Engine

Coolant

Temperature

Sensor

LO HI

OUT

0.5

L/R

CIRCUIT DESCRIPTION

The throttle position (TP) sensor circuit provides a

voltage signal that changes relative to throttle blade

angle. The signal voltage will vary from about 0.25

volts at closed throttle to about 4.75 volts at wide open

throttle (WOT).

The Throttle Position (TP) signal is used by the engine

control module (ECM) for fuel control and most of the

ECM-controlled outputs. The ECM monitors throttle

position and compares actual throttle positions from

the TP sensor to a predicted TP value calculated from

engine speed.

DIAGNOSTIC AIDS

Check for the following conditions:

•Skewed MAP signal or faulty MAP sensor-An

incorrect MAP signal may cause the ECM to

incorrectly calculate the predicted TP sensor value

during high engine load situations. Check for an

unusually low MAP reading.

•Poor connection at ECM-Inspect harness

connectors for backed-out terminals, improper

mating, br oken lock, im pr oper ly form ed or damaged

terminals, and poor terminal-to-wire connection.

•Damaged Harness-Inspect the wiring harness for

damage: An open Circuit, shorts to Ground, or

shorts to Batter y Positive. If the har ness appears to

be OK, observe the TP display on the Scan Tool

while moving connectors and wiring harnesses

related to the sensor. A change in the display will

indicate the location of the fault.

TP SENSOR CIRCUIT RANGE/PERFORMANCE PROBLEM

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check "

performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition ON, engine OFF.

2. Monitor the TP value on the Scan Tool While moving the

throttle between 0% and 100%.

Does the TP value on the Scan Tool move smoothly from 0%

(0.25 volts) to 100% (4.75 volts)?

Go to Step 3 Go to Step 10

1. Ignition OFF.

2. Disconnect the Throttle Position (TP) Sensor electrical

connector, located on the RH side of the Throttle body.

3. Start the engine, and monitor the TP value with the Scan

Tool.

Does the TP value on the Scan Tool hold steadily within the

given range?

0-0.25 volts

Go to Step 5 Go to Step 4

Check the TP sensor signal circuit, between the TP sensor and

the Engine Control Module (ECM), for a short to voltage.

Was the problem found? -

Verify Repair Go to Step 11

Check the TP sensor signal circuit, between the TP sensor and

the ECM, the following conditions:

•A short to ground

•An open circuit

Was the problem found?

Verify Repair Go to Step 6

Check the 5 Volt signal circuit between the TP sensor and the

ECM, for the following conditions:

•An Open Circuit

•A short to ground

•A short to voltage

Was the problem found?

Verify Repair Go to Step 7

STEP ACTION VALUE(S) YES NO

1. Ignition OFF.

2. Place a fused jumper between the TP sensor circuit and the

5 volt signal circuit both at the wiring harness TP sensor

connector.

3. Ignition ON, engine OFF.

4. Observe the TP value displayed on the Scan Tool.

Does the Scan Tool read the following value?

about 5 volts

100%

Go to Step 8 Go to Step 11

Check the TP sensor ground circuit, between the TP sensor and

the ECM, for the following conditions:

•An Open Circuit

•A short to ground

•A short to voltage

Was the problem found?

Verify Repair Go to Step 9

1. Ignition OFF.

2. Place a Digital Multimeter (DVM), set to measure voltage

between the ground circuit and the 5 volt signal circuit, both

at the wiring harness' TP sensor connector.

3. Ignition ON, engine OFF.

Does the DVM indicate the following value?

about 5 volts

Go to Step 10 Go to Step 11

10 Replace the TP sensor.

Verify repair. ---

11 Replace the EPROM or ECM. Note) Refer to 6E1-243. - - -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 22)

THROTTLE POSITION (TP) SENSOR CI RCUIT LOW INPUT

0.5

RED

0.75

GRN

0.75

0.5

GRN

Engine

Control

Module

(ECM)

F14 B1 A3

5 Volt

Reference

Signal

Throttle

Position

(TP)

Sensor

Input

Sensor

Ground

Sensor

Ground

B7 B2

Throttle

Position

(TP)

Sensor

B C A

Manifold

Absolute

Pressure

Sensor

Engine

Coolant

Temperature

Sensor

LO HI

OUT

0.5

L/R

CIRCUIT DESCRIPTION

The throttle position (Throttle Position) sensor circuit

provides a voltage signal that changes relative to

throttle blade angle. The signal voltage will vary from

below 1 volt at closed throttle to about 4 volts at wide

open throttle (WOT).

The Throttle Position signal is used by the engine

control module (ECM) for fuel control and most of the

ECM-controlled outputs. If the ECM detects a low

inpedance short to ground in the Throttle Position

sensor or circuit, then a code 22 will set.

CONDITIO NS FOR SETTING THE DTC

•Throttle Position sensor signal voltage is less than

0.19 volt.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

•The ECM will use a default throttle position based

on RPM.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness - Inspect the wiring harness for

damage. If the harness appears to be OK, observe

the throttle position display on the Scan Tool while

moving connectors and wiring harnesses related to

the throttle Position sensor. A change in the display

will indicate the location of the fault.

DTC (FLASH DTC = 22) THROTTLE POSITION (TP) SENSOR CIRCUIT LOW INPUT

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition ON, engine OFF.

2. With the throttle closed, observe the "Throttle Position

Sensor" display on the Scan Tool. is the "Throttle Position

Sensor" below the specified value? 0.19V

Go to Step 4 Go to Step 3

1. Ignition ON engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

22.

Does the Scan Tool indicate Diagnostic Trouble Code 22 failed? -

Go to Step 4

Refer to

Diagnostic

Aids

1. Ignition OFF.

2. Disconnect the Throttle Position sensor electrical connector.

3. Jumper the 5 volt reference circuit and the Throttle Position

signal together at the Throttle Position sensor harness

connector.

4. Ignition ON.

Observe the "Throttle Position Sensor" value displayed on the

Scan Tool.

Is the "Throttle Position Sensor" at the specified value? 5V

Go to Step 10 Go to Step 5

1. Disconnect jumper.

2. Connect a test light between B+ and the Throttle Position

sensor signal circuit at the Throttle Position sensor harness

connector.

Observe the "Throttle Position Sensor" value displayed on the

Scan Tool.

Is the "Throttle Position Sensor" at the specified value? 5V

Go to Step 6 Go to Step 8

1. Ignition OFF.

2. Disconnect the ECM and check the 5 volt reference circuit

for an open or short to ground.

3. If the 5 volt reference circuit is open or shorted to ground,

repair it as necessary.

Was the 5 volt reference circuit open or shorted to ground?

Verify repair Go to Step 7

STEP ACTION VALUE(S) YES NO

7Check the 5 volt reference circuit for a poor connection at the

ECM and replace the terminal if necessary.

Did the terminal require replacement? -

Verify repair Go to Step 12

1. Ignition OFF.

2. Disconnect the ECM, and check the Throttle Position signal

circuit for an open, short to ground, or short to the sensor

ground circuit.

3. If the Throttle Position sensor signal circuit is open or

shorted to ground, repair it as necessary.

Was the Throttle Position signal circuit open or shorted to

ground?

Verify repair Go to Step 9

Check the Throttle Position sensor signal circuit for a poor

connection at the ECM and replace the terminal if necessary.

Did the terminal require replacement? -

Verify repair Go to Step 12

Check the Throttle Position sensor signal circuit for a poor

connection at the Throttle Position sensor and replace the

terminal if necessary.

Did the terminal require replacement?

Verify repair Go to Step 11

11 Replace the Throttle Position sensor.

Is the action complete? -Verify repair -

12 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 21)

THROTTLE POSITION (TP) SENSOR CI RCUIT HIGH INPUT

0.5

RED

0.75

GRN

0.75

0.5

GRN

Engine

Control

Module

(ECM)

F14 B1 A3

5 Volt

Reference

Signal

Throttle

Position

(TP)

Sensor

Input

Sensor

Ground

Sensor

Ground

B7 B2

Throttle

Position

(TP)

Sensor

B C A

Manifold

Absolute

Pressure

Sensor

Engine

Coolant

Temperature

Sensor

LO HI

OUT

0.5

L/R

CIRCUIT DESCRIPTION

The throttle position (TP) sensor circuit provides a

voltage signal that changes relative to throttle blade

angle. The signal voltage will vary from below 1 volt at

closed throttle to about 4 volts at wide open throttle

(WOT).

The throttle Position signal is used by the engine

control module (ECM) for fuel control and most of the

PCM-controlled outputs. If the ECM detects a low

impedance short to battery in the Throttle Position

sensor or circuit, then a code 21 will set.

CONDITIO NS FOR SETTING THE DTC

•Throttle Position Sensor signal is greater than 4.69

volts.

•Engine revolution is less than 3000rpm and

manifold vacuum is less than 85kpa.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

•The ECM will use a default throttle position based

on RPM. Conditions for Clearing the MIL/DTC

DIAGNOSTIC AIDS

Check for the following conditions:

•Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

•Damaged harness - Inspect the wiring harness for

damage. If the harness appears to be OK, observe

the Throttle Position sensor display on the Scan

Tool while m oving connec tors and wiring harness es

related to the throttle Position sensor. A change in

the display will indicate the location of the fault.

• Faulty Throttle Position sensor - With the ignition

key ON engine OFF observe the Throttle Position

sensor display on the Scan Tool while slowly

depressing the accelerator to wide open throttle. If a

voltage over 4.88 volts is seen at any point in

normal accelerator travel, replace the Throttle

Position sensor.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

7. Components that share the Throttle Position

sensor 5 volt reference circuit include the following

device:

• Engine Coolant Temperature Sensor

• MAP Sensor

Disconnect the component while observing the

Throttle Position sensor display on the Scan Tool. If

the reading changes drastically when this

component is disconnected, replace the component

that affected the reading.

DTC (FLASH DTC = 21) THROTTLE POSITION (TP) SENSOR CIRCUIT HIGH INPUT

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition ON, engine OFF.

2. With the throttle closed, observe the "Throttle Position

Sensor" values displayed on the Scan Tool.

Is the "Throttle Position Sensor" above the specified value? 4.78V

Go to Step 4 Go to Step 3

1. Ignition ON, engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

21.

Does the Scan Tool indicate Diagnostic Trouble Code 21 failed. -

Go to Step 4

Refer to

Diagnostic

Aids

1. Disconnect the Throttle Position sensor electrical connector.

2. Observe the "Throttle Position Sensor" values displayed on

the Scan Tool.

Is the "Throttle Position Sensor" near the specified value? 0V

Go to Step 5 Go to Step 6

Probe the sensor ground circuit at the Throttle Position sensor

harness connector with a test light connected to B+.

Is the test light ON? -

Go to Step 7 Go to Step 10

1. Ignition OFF disconnect the ECM.

2. Ignition ON, engine OFF.

3. Check for a short to voltage on the Throttle Position sensor

signal circuit.

4. If the Throttle Position sensor signal circuit is shorted, repair

it as necessary.

Was the Throttle Position sensor signal circuit shorted?

Verify repair Go to Step 12

STEP ACTION VALUE(S) YES NO

1. Ignition ON.

2. Monitor the "Throttle Position Sensor" Scan Tool display

while disconnecting each of the components that share the 5

volt reference circuit (one at a time).

3. If the "Throttle Position Sensor" values displayed changes,

replace the component that caused the display to change

when disconnected.

Does disconnecting any of these components cause the

"Throttle Position Sensor" values displayed to change?

Verify repair Go to Step 8

1. Ignition OFF disconnect the ECM.

2. Ignition ON, engine OFF.

3. Check for a short to B+ on the 5 volt reference circuit.

4. If the 5 volt reference circuit is shorted, repair it as

necessary.

Was the 5 volt reference circuit shorted?

Verify repair Go to Step 9

9Check for poor electrical connections at the Throttle Position

Sensor and replace terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 11

1. Ignition OFF.

2. Disconnect the ECM, and check for an open sensor ground

circuit to the Throttle Position Sensor.

3. If a problem is found, repair it as necessary.

Was the sensor ground circuit to the Throttle Position Sensor

open?

Verify repair Go to Step 12

11 Replace the Throttle Position Sensor.

Is the action complete? -Verify repair -

12 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 13) O2 SENSOR

CIRCUIT NOT READY DETECTED (IF APPLICABLE)

CIRCUIT DESCRIPTION

•The engine control module (ECM) supplies a bias

voltage of about 450mV between the heated

oxygen sensor (HO2S) high and low circuits. W hen

meas ured with a 10 m egaohm digital voltm eter, this

may display as low as 320mV. The oxygen sensor

varies the voltage within a range of about 900mV

when the ex haust is r ich, down through about 60mV

when exhaust is lean. The ECM cons tantly monitors

the HO2S signal during "Closed Loop" operation

and compensates for a rich or lean condition by

decreasing or increasing injector pulse width as

necessary. This code determines whether the

oxygen sensor is ready for use as a feedback for

fuel control system. Then the DTC 13 will set.

CONDITIO NS FOR SETTING THE DTC

•Engine run time is longer than 60 seconds.

All the above conditions are met and the following

condition is met:

•HO2S signal voltage remains between 343mV and

540mV.

•Throttle angle is greater than 5%.

•ECT greater than 70°C.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the second time the fault is detected.

•"Open Loop" fuel control will be in effect.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection or damaged harness - Inspect the

harness connectors for backed-out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, poor terminal-to-wire

connection, and damaged harness.

• Faulty HO2S heater or heater circuit - With the

ignition ON engine OFF after a cool down period,

the HO2S voltage displayed on the Scan Tool is

normally 455-460mV. A reading over 1000mV

indicates a signal line shorted to voltage. A reading

under 5mV indicates a signal line shorted to ground

or signal lines shorted together. Disconnect the

HO2S and connect a test light between the HO2S

battery feed and heater ground circuits. If the test

light does not light for 2 seconds when the ignition

is turned on, repair the open battery feed or sensor

ground circuit as necessary. If the test light lights

and the HO2S signal and low circuits are OK,

replace the HO2S.

• Intermittent test - With the ignition ON monitor the

HO2S signal voltage while moving the wiring

harness and related connectors. If the fault is

induced, the HO2S signal voltage will change. This

may help isolate the location of the malfunction.

DTC (FLASH DTC = 13) O2 SENSOR CIRCUIT NOT READY

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Install the Scan Tool.

2. Run the engine at operating temperature.

3. Operate the engine above 1200 RPM for three minutes.

Does the Scan Tool indicate HO2S voltage varying outside the

specified values? 400-500mV Go to Step 3 Go to Step 4

1. Ignition ON, engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

13.

3. Note the test result.

Does the Scan Tool indicate Diagnostic Trouble Code 13 failed

this ignition?

Go to Step 4

Refer to

Diagnostic

Aids

4Check for a damaged harness.

Was a problem found? -Verify repair Go to Step 5

Check for poor HO2S high and low circuit terminal connections

at the HO2S harness connector and replace terminal(s) if

necessary.

Did any terminals require replacement?

Verify repair Go to Step 6

Check for poor HO2S high and low circuit terminal connections

at the ECM and replace terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 7

STEP ACTION VALUE(S) YES NO

1. Ignition OFF.

2. With the ECM disconnected, check continuity of the HO2S

high circuit.

3. If the HO2S high circuit measures over 0.5 ohms, repair

open or poor connection as necessary.

Was a HO2S high circuit problem found and corrected?

Verify repair Go to Step 8

1. Ignition OFF.

2. With the ECM disconnected, check continuity of the HO2S

low circuit.

3. If the HO2S low circuit measures over 5 ohms, repair open

or poor connection as necessary.

Was a HO2S low circuit problem found and corrected?

Verify repair Go to Step 9

1. Ignition ON, engine OFF.

2. Disconnect HO2S and jumper the HO2S high and low

circuits (ECM side) to ground.

3. Using a Scan Tool, monitor HO2S voltage.

Is HO2S voltage approximately equal to the specified value? 10mV Go to Step 10 Go to Step 11

10 Replace HO2S.

Is the action complete? -Verify repair -

11 Replace the EPROM or ECM. Note) Refer to 6E1-243.

Is the action complete? -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 44)

O2 SENSOR TOO LEAN (IF APPLICABLE)

CIRCUIT DESCRIPTION

The engine control module (ECM) supplies a bias

voltage of about 450mV between the heated oxygen

sensor (HO2S) signal and low circuits. When

measured with a 10 megaohm digital voltmeter, this

may display as low as 350mV. The oxygen sensor

varies the voltage within a range of about 900mV

when the exhaust is rich, down through about 60mV

when exhaust is lean. The ECM constantly monitors

the HO2S signal during "Closed Loop" operation and

compensates for a rich or lean condition by

decreasing or increasing injector pulse width as

necessary. If the HO2S voltage remains excessively

low for an extended period of time.

This code detects a lean oxygen sensor reading.

CONDITIO NS FOR SETTING THE DTC

•Engine run time is longer than 60sec.

•Engine coolant temperature is above 70 °C(158°F).

•Throttle angle is greater than 5%.

All above conditions met and the following condition is

met:

•HO2S signal voltage remains less than 274mV.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

•"Open Loop" fuel control will be in effect.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

•Heated oxygen sensor wiring - The sensor pigtail

may be routed incorrectly and contacting the

exhaust system.

•Poor ECM to engine block ground.

•Fuel pressure - The system will go lean if pressure

is too low. The ECM can compensate for some

decrease. However, if fuel pressure is too low, a

diagnostic Trouble Code 44 may be set. Refer to

Fuel System Diagnosis .

•Lean injector(s) - Perform "Injector Balance Test."

•Vacuum leaks - Check for disconnected or

damaged vacuum hoses and for vacuum leaks at

the intake manifold, throttle body, and PCV system.

•Exhaust leaks - An exhaus t leak m ay cause outside

air to be pulled into the exhaust gas stream past the

HO2S, causing the system to appear lean. Check

for exhaust leaks that may cause a false lean

condition to be indicated.

•Fuel contam ination - Water, even in sm all am ounts,

can be delivered to the f uel inj ect ors . The water c an

cause a lean exhaust to be indicated, Excessive

alcohol in the fuel can also cause this condition.

Refer to Fuel System Diagnosis for the procedure

to check for fuel contamination.

If none of the above conditions are present, replace

the affected HO2S.

DTC (FLASH DTC = 44) O2 SENSOR TOO LEAN

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Install the Scan Tool.

2. Run the engine at operating temperature.

3. Operate the vehicle within the parameters specified under

"Conditions for Setting the Diagnostic Trouble Code" criteria

included in Diagnostic Support.

4. Using a Scan Tool, monitor HO2S voltage.

Does the HO2S voltage remain below the specified value? 300mV Go to Step 4 Go to Step 3

31. Ignition ON, engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

44. -Go to Step 4 Refer to

Diagnostic

Aids

1. Turn the ignition OFF.

2. Disconnect the ECM.

3. Check the HO2S high and low circuits for a short to ground

or a short to the heater ground circuit.

Are the HO2S signal circuits shorted to ground?

Go to Step 5 Go to Step 6

5Repair the HO2S signal circuit.

Is the action complete? -Verify repair -

1. Turn the ignition OFF HO2S and ECM disconnected.

2. Check for continuity between the high and low signal circuits.

Was there continuity between the high and low circuits? -

Go to Step 7 Go to Step 8

7Repair the short between the high and low circuits.

Is the action complete? -Verify repair -

1. Ignition OFF.

2. Reconnect the ECM, leave the sensor disconnected.

3. Ignition ON.

Does the Scan Tool indicate HO2S voltage near the specified

value? 430-450mV

Refer to

Diagnostic

Aids Go to Step 9

9Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 45)

O2 SENSOR TOO RICH (IF APPLICABLE)

CIRCUIT DESCRIPTION

The engine control module (ECM) supplies a bias

voltage of about 450mV between the heated oxygen

sensor (HO2S) signal and low circuits. When

measured with a 10 megaohm digital voltmeter, this

may display as low as 320mV. The oxygen sensor

varies the voltage within a range of about 900mV

when the exhaust is rich, down through about 10mV

when exhaust is lean. The ECM constantly monitors

the HO2S signal during "Closed Loop" operation and

compensates for a rich or lean condition by

decreasing or increasing injector pulse width as

necessary. If the HO2S voltage remains excessively

high for an extended period of time.

This code detects a rich oxygen sensor reading.

CONDITIO NS FOR SETTING THE DTC

•Engine run time is longer than 60sec.

•Engine coolant temperature is above 70°C(158°F).

•Throttle angle is greater than 5%.

•Following Diagnostic Trouble Codes are not set:

Malfunction DTC: 21, 22, 33, 24

•Closed Loop fuel integrator is not reset and closed

loop fuel enabled.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL).

•"Open Loop" fuel control will be in effect.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check the following items:

•Fuel pressure - The system will go rich if pressure

is too high. The ECM can compensate for some

increase. However, if fuel pressure is too high, a

Diagnostic Trouble Code 45 may be set. Refer to

Fuel System Diagnosis .

•Perform "Injector Balance Test" - Refer to

Fuel System Diagnosis .

•Check the EVAP canister for fuel saturation - If full

of fuel, check canister control and hoses. Refer to

Evaporative (EVAP) Emission Control System.

•Check for a leak in the fuel pressure regulator

diaphragm by checking the vacuum line to toe

regulator for the presence of fuel.

•An intermittent TP sensor output will cause the

system to go rich due to a false indication of the

engine accelerating.

•Silicon contamination of the HO2S can also cause a

high HO2S voltage to be indicated. T his c ondition is

indicated by a powdery white deposit on the portion

of the HO2S exposed to the exhaust stream. If

contamination is noticed, replace the affected

HO2S.

•Operate the vehicle while monitoring the HO2S

voltage with a Scan Tool. If the HO2S voltage is

limited within a range between 300mV to 600mV,

check the HO2S high and low circuit wiring and

associated terminal connections. If the wiring and

connections are OK, replace the HO2S.

DTC (FLASH DTC = 45) O2 SENSOR TOO RICH

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Install the Scan Tool.

2. Run the engine at operating temperature.

3. Operate the vehicle within parameters specified under

"Conditions for Setting the Diagnostic Trouble Code".

4. Using a Scan Tool, monitor HO2S voltage.

Does the HO2S voltage remain above the specified value?

952 mV

(500mV in

deceleration

fuel cutoff

mode) Go to Step 4 Go to Step 3

1. Ignition ON.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

45.

3. Does the Scan Tool indicate Diagnostic Trouble Code 45. -Refer to

Diagnostic

Aids Go to Step 4

1. Ignition OFF.

2. Disconnect HO2S.

3. Ignition ON.

4. At HO2S connector (ECM side) use a DVM to measure

voltages at the high and low signal terminals.

Are the voltages in the specified range? 5-14V Go to Step 5 Go to Step 6

5 Repair short to voltage in signal circuit. - Verify repair -

1. Ignition OFF.

2. Disconnect the ECM connector.

3. Check for damage to the ECM pins and terminals.

Was a problem found?

Verify repair Go to Step 7

1. Ignition ON, engine OFF.

2. Disconnect HO2S and jumper the HO2S high and low

circuits (ECM side) to ground.

3. Using a Scan Tool, monitor HO2S voltage.

Is HO2S voltage below the specified value? 10mV Go to Step 8 Go to Step 9

8Replace HO2S.

Is the action complete? -Verify repair -

9Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 14) ENGINE COOLANT

TEMPERATURE (ECT) SENSOR CIRCUIT HIGH INPUT

0.75

0.5

GRN

0.5

L/R

Engine

Control

Module

(ECM)

A3 F14

ECT

Sensor

Input

Sensor

Ground

Engine

Coolant

Temperature

(ECT)

Sensor

TPS

HI OUT LO

CIRCUIT DESCRIPTION

The engine coolant temperature (ECT) sensor is a

thermistor mounted in the engine coolant stream. The

engine control module (ECM) applies a voltage (about

5 volts) through a pull-up resistor to the ECT signal

circuit. When the engine coolant is cold, the sensor

(thermistor) resistance is high, therefore the ECM will

measure a high signal voltage. As the engine coolant

warms, the sensor resistance becomes lower, and the

ECT signal voltage measured at the ECM drops. With

a fully warmed up engine, the ECT signal voltage

should measure about 1.5 to 2.0 volts. If the ECM

detect a continuous open in the ECT sensor or circuit,

then a code 14 will set.

CONDITIO NS FOR SETTING THE DTC

•Engine running time is longer than 10secs.

•The ECT sensor signal indicates an engine coolant

temperature greater than 140°C (284°F).

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) fault is detected.

•The ECM will substitute the ECT reading with a

default engine coolant temperature value. The

default value is based on start-up intake air

temperature and running time.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

•Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

•Damaged harness - Inspect the wiring harness for

damage, If the harness appears to be OK, observe

the ECT display on the Scan Tool while moving

connectors and wiring harnesses related to the ECT

sensor. A change in the ECT display will indicate

the location of the fault.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. Verifies that the fault is present.

3. Refer to the "Temperature vs. Resistance Value"

table. The table may be used to test the ECT

sensor at various temperatures to evaluate the

possibility of a "shifted" sens or that m ay be stored

above or below a certain temperature. If this is the

case, replace the ECT sensor. If the ECT sensor

appears to be OK, the fault is intermittent; refer to

Diagnostic Aids.

ENGINE COOLANT TEMPERATURE SENSOR

°C °F OHMS

Temperature vs. Resistance Values

(approximate)

100 212 177

80 176 332

60 140 667

45 113 1188

35 95 1802

25 77 2796

15 59 4450

5 41 7280

−5 23 12300

−15 5 21450

−30 −22 52700

−40 −40 100700

DTC (FLASH DTC = 14) ECT SENSOR CIRCUIT HIGH INPUT

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition ON engine OFF

2. Observe the "Eng Coolant Temp" displayed on the Scan

Tool.

Is the "Eng Coolant Temp" below the specified value? −35°C

(−31°F) Go to Step 4 Go to Step 3

1. Ignition ON engine OFF.

2. Using a Scan Tool, monitor the info for Diagnostic Trouble

Code 14.

Does the Scan Tool indicate Diagnostic Trouble Code 14.

-Refer to Test

Description

Refer to

Diagnostic

Aids

1. Disconnect the ECT sensor electrical connector.

2. Jumper the ECT signal circuit and the sensor ground circuit

together at the ECT sensor harness connector.

3. Observe the "Eng Coolant Temp" displayed on the Scan

Tool.

Is the "Eng Coolant Temp" at the specified value? 140°C

(284°F) Go to Step 6 Go to Step 5

1. Jumper the ECT signal circuit at the ECT sensor harness

connector to chassis ground.

2. Observe the "Eng Coolant Temp" displayed on the Scan

Tool.

Is the "Eng Coolant Temp" at the specified value? 140°C

(284°F) Go to Step 7 Go to Step 6

6Check for poor connections at the ECT sensor and replace

terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 8

1. Ignition OFF.

2. Disconnect the ECM, and check the ECT sensor ground

circuit for an Short to ground.

3. If the ECT sensor ground circuit is Short to ground, repair it

as necessary.

Was the ECT sensor ground circuit Short to ground?

Verify repair Go to Step 8

Check for a poor sensor ground or ECT signal circuit terminal

connection at the ECM and replace terminal(s) if necessary.

Did any of the terminal need to be replaced? -

Verify repair Go to Step 9

9Replace the ECT sensor.

Is the action complete? -Verify repair -

10 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -

Verify repair

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 15) ENGINE COOLANT

TEMPERATURE (ECT) SENSOR CIRCUIT LOW INPUT

0.75

0.5

GRN

0.5

L/R

Engine

Control

Module

(ECM)

A3 F14

ECT

Sensor

Input

Sensor

Ground

Engine

Coolant

Temperature

(ECT)

Sensor

TPS

HI OUT LO

CIRCUIT DESCRIPTION

The ECT sensor is a thermistor mounted in the engine

coolant stream. The engine control module (ECM)

applies a voltage (about 5 volts) through a pull-up

resistor to the ECT signal circuit. When the engine

coolant is cold, the sensor (thermistor) resistance is

high, therefore the ECM will measure a high signal

voltage. As the engine coolant warms, the sensor

resistance becomes lower, and the ECT signal voltage

measured at the ECM drops. With a fully warmed-up

engine, the ECT signal voltage should measure about

1.5 to 2.0 volts.

CONDITIO NS FOR SETTING THE DTC

•Engine running time is longer than 30 secs.

•The ECT sensor signal indicates an engine coolant

temperature less than -35°C (-31°F).

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

•The ECM will substitute the ECT reading with a

default engine coolant temperature value. The

default value is based on start-up intake air

temperature and running time.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

•Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

•Damaged harness - Inspect the wiring harness for

damage, If the harness appears to be OK, observe

the ECT display on the Scan Tool while moving

connectors and wiring harnesses related to the ECT

sensor. A change in the ECT display will indicate

the location of the fault.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. Verifies that the fault is present.

3. Refer to the "Temperature vs. Resistance Value"

table. The table may be used to test the ECT

sensor at various temperatures to evaluate the

possibility of a "shifted" sens or that m ay be stored

above or below a certain temperature. If this is the

case, replace the ECT sensor. If the ECT sensor

appears to be OK, the fault is intermittent; refer to

Diagnostic Aids.

ENGINE COOLANT TEMPERATURE SENSOR

°C °F OHMS

Temperature vs. Resistance Values

(approximate)

100 212 177

80 176 332

60 140 667

45 113 1188

35 95 1802

25 77 2796

15 59 4450

5 41 7280

−5 23 12300

−15 5 21450

−30 −22 52700

−40 −40 100700

DTC (FLASH DTC = 15) ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT LOW INPUT

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2 1. Ignition ON, engine OFF

2. Observe the "Eng Coolant Temp" displayed on the Scan

Tool.

Is the "Eng Coolant Temp" below the specified value? 140°C

(284°F) Go to Step 4 Go to Step 3

1. Ignition ON, engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

15.

Does the Scan Tool indicate Diagnostic Trouble Code 15?

Go to Step 4

Refer to

Diagnostic

Aids

1. Disconnect the ECT sensor electrical connector.

2. Observe the "Eng Coolant Temp" displayed on the Scan

Tool.

Is the "Eng Coolant Temp" at the specified value? −35°C

(−31°F) Go to Step 6 Go to Step 5

1. Ignition OFF.

2. Disconnect the ECM and check the ECT circuit for a an open

or a short to battery in the sensor circuit.

3. If the ECT circuit is short to battery or open, repair it as

necessary.

Was the ECT signal circuit shorted to ground?

Verify repair Go to Step 7

6Replace the ECT sensor.

Is the action complete? -Verify repair -

7Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 16)

KNOCK SENSOR (KS) DISCONNECTED MALFUNCTI ON

CIRCUIT DESCRIPTION

The knock sensor (KS) system is used to detect

engine detonation. The knock sensor produced an AC

voltage signal. The knock sensor sends this signal to

the ECM. The amplitude and the frequency of the AC

voltage signal depends upon the knock level being

detected. The ECM will then retard the spark timing

based on the signals from the Knock Sensor.

This code detects a disconnected knock sensor. Then

a DTC 16 will set.

CONDITIO NS FOR SETTING THE DTC

•Electronic and spark control enabled.

•Engine running.

•ECM powered up.

•Engine speed is greater than 2400rpm.

All the above mentioned conditions are met.

ACTIO N TAKEN WHEN THE DTC SETS

•The Malfunc tion Indic ator Lamp (MIL) will illum inate

the fault is detected.

•The ECM will use a c alculated spark retard value in

order to minimize the knock during the conditions

when the knock is likely to occur. The calculated

value will vary based on the engine speed and load.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Correct any abnormal engine noise before using the

diagnostic table.

Check for an open ignition feed circuit.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Table.

2. If the conditions for the test as described above are

met, a Diagnostic Trouble Code 16 will set and MIL

will illuminate.

4. If the engine has an internal knock or audible noise

that causes a knocking type noise on the engine

block, the knock sensor may be responding to the

noise.

6. Any circuitry, that is suspected as causing the

complaint, should be thoroughly checked for

backed out terminals, improper mating, broken

locks, improperly formed or damaged terminals,

poor terminal to wiring connections or physical

damage to the wiring harness.

8. Checking the internal resistance of the knock

sensor verifies if the knock sensor or the wiring to

the knock sensor is OK.

DTC (FLASH DTC = 16) KS SENSOR DISCONNECTED MALFUNCTION

STEP ACTION VALUE(S) YES NO

Was the Powertrain On-Board Diagnostic (OBD) System Check

performed? -

Go to Step 2

Go to

Powertrain

OBD System

Check

1. Start the engine.

2. Install a Scan Tool.

3. Clear the Diagnostic Trouble Codes.

4. Run the engine at slightly more than 10% throttle angle.

Does the Malfunction Indicator Lamp (MIL) illuminate?

Go to Step 4 Go to Step 3

31. Turn the ignition Switch ON, with engine OFF.

Does the Malfunction Indicator Lamp (MIL) illuminate? -Go to Step 4 Go to Step 12

4Listen to the engine while raising and lowering the engine

speed.

Is a knock or audible noise present? -

Go to Step 5 Go to Step 6

5Repair the mechanical engine problem or a loose bracket or

component.

Is the action complete? -

Go to Step 12

6Check for a poor connection at the ECM connector,

Knock sensor signal circuit and repair as necessary.

Was a repair necessary? -

Go to Step 12 Go to Step 7

7Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Go to Step 12 -

STEP ACTION VALUE(S) YES NO

1. Turn the ignition switch OFF.

2. Disconnect the ECM connectors at the ECM.

3. With a Digital Voltmeter (DVM) connected to ground,

measure the resistance of the knock sensor through the

knock sensor signal circuit.

Is the measured value wi thin the specified value?

95K-105K

OHMS

Go to Step 6 Go to Step 9

9Check the knock sensor electrical connector for a poor

connection and repair as necessary.

Was a repair necessary? -

Go to Step 12 Go to Step 10

10 Check the knock sensor signal circuit for an open or a short to

ground or to voltage and repair as necessary.

Was a repair necessary? -

Go to Step 12 Go to Step 11

11 Replace the Knock Sensor(KS).

Is the action complete? -Go to Step 12 -

1. Using the Scan Tool, clear the Diagnostic Trouble Codes.

2. Start the engine and idle at normal operating temperature.

3. Operate the vehicle within the conditions for setting this

Diagnostic Trouble Code as specified in the supporting text.

Does the Scan Tool indicate that this diagnostic has ran and

passed? -

Go to Step 13 Go to Step 2

Check is any additional Diagnostic Trouble Codes are set.

Are any Diagnostic Trouble Codes displayed that have not been

diagnosed? -

Go to

applicable

Diagnostic

Trouble Code

table System OK

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 18) DIGITALLY

CONTROLED SIGNAL TO NOISE ENHANCEMENT FILTER FAILURE

CIRCUIT DESCRIPTION

The knock sensor (KS) system is used to detect

engine detonation. The knock sensor produced an AC

voltage signal. The knock sensor sends this signal to

the ECM. The amplitude and the frequency of the AC

voltage signal depends upon the knock level being

detected. The ECM will then retard the spark timing

based on the signals from the Knock Sensor.

This code detects a digitally controlled signal to noise

enhancement filter failure. Then the DTC 18 will set.

CONDITIO NS FOR SETTING THE DTC

•ECM powered up, Engine running, Electronic spark

control enabled and Engine rpm is greater than 96

rpm.

•Malfunction 16 is not triggered.

ACTIO N TAKEN WHEN THE DTC SETS

•The Malfunc tion Indic ator Lamp (MIL) will illum inate

the second time the fault is detected.

•The ECM will use a c alculated spark retard value in

order to minimize the knock during the conditions

when the knock is likely to occur. The calculated

value will vary based on the engine speed and load.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Correct any abnormal engine noise before using the

diagnostic table.

Check for an open ignition feed circuit.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Table.

2. If the conditions for the test as described above are

met, a Diagnostic Trouble Code 18 will set and MIL

will illuminate.

5. Any circuitry, that is suspected as causing the

complaint, should be thoroughly checked for

backed out terminals, improper mating, broken

locks, improperly formed or damaged terminals,

poor terminal to wiring connections or physical

damage to the wiring harness.

9. If the KS module was previously replaced and the

Diagnostic Trouble Code resets, a malfunctioning

ECM is indicated.

DTC (FLASH DTC = 18) DIGITALLY CONTROLLED SIGNAL

TO NOISE ENHANCEMENT FILTER FAILURE

STEP ACTION VALUE(S) YES NO

Was the On-Board Diagnostic(OBD) System Check performed?

Go to Step2

Go to

Powertrain

OBD System

Check

1. Operate the engine within the conditions specified in the

diagnostic support Conditions for Setting the Diagnostic

Trouble Code.

2. Using a Scan Tool, monitor the Specific DTC information for

DTC 18.

3. Observe the test results.

Does the Scan Tool indicate the DTC 18.

Go to Step 3

Go to

Diagnostic

Aids

1. Turn ON the ignition with the engine leaving OFF.

2. Disconnect the KS electrical connector.

3. Using a Digital Voltmeter (DVM), measure the voltage

between the KS signal circuit at the knock sensor harness

connectors and ground.

Is the voltage at the specified value? Approx.5.0V Go to Step 4 Go to Step 7

Measure the resistance of the KS sensor by connecting the

between the KS sensor terminal and the engine block.

Is the resistance of the KS sensor near the specified value? 100K OHMS Go to Step 5 Go to Step 8

1. Check the KS signal circuit for a poor terminal connection at

the knock sensor.

2. If a problem is found, repair as necessary. Refer to Wiring

Repairs in Engine Electrical.

Was a problem found?

Go to Step 6 Go to Step 8

1. Re-Connect the KS Sensor in order to monitor the voltage

between the KS sensor terminal and the engine ground.

2. Tap on the engine lift bracket, near the KS Sensor, while

observing the signal indicated on the Scan Tool.

Is any signal indicated on the while tapping on the engine lift

bracket?

Go to Step 10 Go to Step 7

STEP ACTION VALUE(S) YES NO

1. Turn OFF the ignition.

2. Disconnect the ECM.

3. Turn ON the ignition.

4. Check the KS signal circuit between the ECM and the KS

sensor connector for an open, a short to voltage, or a short

to ground.

5. If a wiring problem is found, repair as necessary.

Was a problem found?

Go to Step 10 Go to Step 9

8Replace the KS Sensor. Refer to Knock Sensor.

Is action complete? -Go to Step 10 -

9Replace the EPROM or ECM. Note) Refer to 6E1-243.

Is the action complete? -Go to Step 10 -

1. Using the Scan Tool, select the DTC and the Clear Info.

2. Start the Engine.

3. Idle at the normal operating temperature.

4. Select Specific DTC.

5. Enter the DTC number which was set.

6. Operate the vehicle within the conditions for setting this DTC

as specified in the supporting text.

Does the Scan Tool indicate that this diagnostic ran and

passed?

Go to Step 11 Go to Step 2

Using the Scan Tool, select the Capture Info and the Review

Info.

Are any DTC displayed that have not been diagnosed? -

Go to the

applicable

Diagnostic

Trouble Code

table System OK

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 19)

CRANKSHAFT POSITION (CKP) SENSOR SI GNAL INCORRECT

Engine

Control

Module

(ECM)

CKP

Sensor

Input

Sensor

Ground

0.5

Crankshaft

Position

(CKP)

Sensor

CIRCUIT DESCRIPTION

The 58X reference signal is produced by the

crankshaft position (CKP) sensor. During one

crankshaft revolution, 58 crankshaft pulses will be

produced. The engine control module (ECM) uses the

58X reference signal to calculate engine RPM and

crankshaft position. The ECM constantly monitors the

number of pulses on the 58X reference circuit. If the

ECM receives an incorrect number of pulses on the

58X reference circuit, Diagnostic Trouble Code 19 will

set.

CONDITIO NS FOR SETTING THE DTC

•Engine is running.

•Number of revolutions with pulses not equal to 58 is

greater than 20.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) after the fault is detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection,

rubbed-through wire insulation or a wire broken inside

the insulation. Check for:

• Poor connection - Inspect the ECM harness and

connectors for improper mating, broken locks,

improperly formed or damaged terminals, and poor

terminal-to-wire connection.

• Damaged harness - Inspect the wiring harness for

damage; shorts to Ground, shorts to Battery

Positive, and Open circuits. If the harness appears

to be OK, disconnect the ECM, turn the ignition on

and observe a voltmeter connected to the 58X

reference circuit at the ECM harness connector

while moving connectors and wiring harnesses

related to the ECM. A change in voltage will indicate

the location of the fault.

• This code detects an incorrect 58X signal caused

by intermittent failures.

DTC (FLASH DTC = 19) CRANKSHAFT POSITION (CKP) SENSOR SIGNAL INCORRECT

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

Attempt to start the engine.

Does the engine start? -

Go to Step 3

Refer to

Engine Cranks

But Will Not

Run chart

1. Clear Diagnostic Trouble Code 19.

2. Start the engine and idle for 1 minute.

3. Observe Diagnostic Trouble Codes.

Is Diagnostic Trouble Code 18 set?

Go to Step 4

Refer to

Diagnostic

Aids

1. Disconnect the ECM and CKP sensor.

2. Check for an open or a short to ground in the 58X reference

circuit between the CKP sensor connector and the ECM

harness connector.

3. If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 5

1. Reconnect the ECM and CKP sensor.

2. Connect a Digital Voltmeter (DVM) to measure voltage on

the 58X reference circuit at the ECM connector.

3. Observe the voltage while cranking the engine.

Is the voltage near the specified value? 2.5V

Go to Step 8 Go to Step 6

6Check the connections at the CKP sensor and replace the

terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 7

7Replace the CKP sensor.

Is the action complete? -Verify repair -

8Check connections at the ECM and replace the terminals if

necessary.

Did any terminals require replacement? -

Verify repair Go to Step 9

9Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 24)

VEHICLE SPEED SENSOR (VSS) FAULT

CIRCUIT DESCRIPTION

The vehicle speed sensor has a magnet rotated by the

transmission output shaft. Attached to the sensor is a

hall effect circuit that interacts with the magnetic field

created by the rotating magnet. A 12-volt operating

supply for the speed sensor hall circuit is supplied

from the meter fuse. The VSS pulses to ground the 5-

volt signal sent from the engine control module (ECM)

on the reference circuit. The ECM interprets vehicle

speed by the number of pulses to ground per second

on the reference circuit. Then a DTC 24 will set.

CONDITIO NS FOR SETTING THE DTC

•Vehicle speed is less than 3 km/h.

•Engine is running.

•MAP is less than 24kPa.

•Throttle closed and in Drive.

•Engine Speed is between 2000 RPM and 5000

RPM.

•Following malf unctions are not set: DT C 21, 22, 33,

34 are not set.

When the above conditions are met, one of the

following tests will run:

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the fault is detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•Poor connection at the ECM: Inspect harness

connectors for backed out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal to wire

connection.

•Damaged harness: Inspect the wiring harness to

the Speedometer, Tachometer and check Engine

Lamp for an intermittent open or intermittent short

circuit.

DTC (FLASH DTC = 24) VEHICLE SPEED SENSOR (VSS) FAULT

STEP ACTION VALUE(

S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -Go to Step 2

Go to OBD

System Check

1. Ignition OFF.

2. Disconnect the VSS connector.

3. Using a test light to battery +, probe the connector ground

wire.

Did the light illuminate?

Go to Step 4 Go to Step 3

3 Repair the open in the sensor ground circuit. - Verify repair -

1. Ignition ON.

2. Using a Digital Voltmeter (DVM), measure at the VSS

connector between ground and voltage supply.

Was the measurement near the specified value?

Battery

voltage

Go to Step 6 Go to Step 5

5 Repair the open or short to ground in the sensor circuit. - Verify repair -

1. Ignition OFF.

2. Check the white wire between the VSS sensor connector

and the ECM for the following conditions:

•An open circuit

•A short to ground

Was the faulty condition located?

Verify repair Go to Step 9

7Using a DVM, measure the resistance between the VSS sensor

body and transmission case (ground).

Is the resistance above the specified value?

10K

OHMS Verify repair Go to Step 9

81. Remove the VSS from the transmission c ase.

2. Visually inspect the VSS for damage.

Does the VSS appear to be OK? -Verify repair -

9 Replace the VSS - Verify repair -

10 Replace the EPROM or ECM.

Verify repair. Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 33)

MANIFOLD ABSOLUTE PRESSURE (MAP) TOO HIGH

0.5

YEL/

GRN

0.5

GRN

0.5

RED

0.5

RED

0.5

GRN

0.5

RED

Manifold

Absolute

Pressure

(MAP)

Sensor

F10 B2

0.5

GRN

B7 A3

5 Volt

Reference

Signal

MAP Sensor

Input

Sensor

Ground

0.75

AB C

Intake

Air Temperature

Sensor

Throttle Position

Sensor

Engine

Control

Module

(ECM)

HI OUT LO

0.5

CIRCUIT DESCRIPTION

The manifold absolute pressure (MAP) sensor

responds to changes in intake manifold pressure.

The MAP sensor signal voltage to the engine control

module (ECM) varies from below 2 volts at idle (low

manifold pressure) to above 4 volts with the ignition

ON, engine not running or at wide-open throttle (high

manifold pressure).

A "speed density" method of determining engine

load is used. This is calculated using inputs from the

MAP sensor, the CKP Sensor, and the Intake Air

Temperature (IAT) sensor. The MAP sensor is the

main sensor used in this calculation, and measuring

engine load is its main function. The ECM monitors

the MAP signals for voltages outside the normal

range of the MAP sensor. This code defects a short

to MAP signal voltage in the MAP sensor circuit.

Diagnostic Trouble Code 33 will be set.

CONDITIO NS FOR SETTING THE DTC

• No TP sensor Diagnostic Trouble Codes 21 or 22

present.

• Engine is running.

• Not in power enrich mode.

•Throttle Position Sensor value is less than 1%.

• Altitude Compensated Manifold Absolute Pressure

is greater than 95kpa.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL).

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear

them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness - Inspect the wiring harness for

damage, shorts to Ground, shorts to Battery

positive, and Open circuits. If the harness appears

to be OK, observe the MAP display on the Scan

Tool while moving connectors and wiring

harnesses related to the sensor. A change in the

display will indicate the location of the fault.

DTC (FLASH DTC = 33) MANIFOLD ABSOLUTE PRESSURE (MAP) TOO HIGH

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. If the engine idle is rough, unstable or incorrect, repair the

idle problem before using this chart.

Refer to Symptoms section.

2. With the engine idling, note the MAP value on the Scan Tool.

Is the MAP reading above the specified value?

About 4V

90 kPa

Go to Step 4 Go to Step 3

1. Ignition ON engine OFF.

2. Using the Scan Tool, monitor info for Diagnostic Trouble

Code 33.

Does the Scan Tool indicate Diagnostic Trouble Code 33 failed? -

Go to Step 4

Refer to

Diagnostic

Aids

1. Ignition OFF.

2. Disconnect the MAP sensor electrical connector.

3. Ignition ON.

4. Observe the MAP value displayed on the Scan Tool.

Is the MAP value near the specified value? 0V

10.3 Kpa Go to Step 5 Go to Step 6

Check the MAP sensor signal circuit, between the MAP sensor

and the Engine control Module (ECM), for a short to voltage.

Was the problem found? -

Verify Repair Go to Step 12

Check the MAP sensor signal circuit, between the MAP sensor

and the ECM for the following conditions:

•A short to ground

•An open circuit

Was the problem found?

Verify repair Go to Step 7

STEP ACTION VALUE(S) YES NO

Check the 5 volt signal circuit, between the MAP sensor and the

ECM for the following conditions:

•A short to ground

•An open circuit

•A short to voltage

Was the problem found?

Verify Repair Go to Step 8

1. Ignition OFF.

2. Place a fused jumper between the MAP sensor circuit and

the 5 volt signal circuit, both at the wiring harness' MAP

sensor connector.

3. Ignition ON, Engine OFF.

4. Observe the MAP value displayed on the Scan Tool.

Does the Scan Tool read the following value?

5 Volts

104 kPa

Go to Step 9 Go to Step 12

Check the MAP sensor ground circuit, between the MAP sensor

and the ECM, for the following conditions:

•A short to ground

•An open circuit

•A short to voltagen

Was the problem found?

Verify Repair Go to Step 10

1. Ignition OFF.

2. Place a Digital Multimeter (DVM), set to measure voltage

between the ground circuit and the 5 volt signal circuit, both

at the wiring harness' MAP sensor connector.

3. Ignition ON, Engine OFF.

Does the DVM read the following value?

5 Volts

Go to Step 11 Go to Step 12

11 Replace the MAP Sensor.

Verify Repair. ---

12 Replace the EPROM or ECM.

Verify Repair. Note) Refer to 6E1-243. ---

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 34)

MANIFOLD ABSOLUTE PRESSURE (MAP) TOO LOW

0.5

YEL/

GRN

0.5

GRN

0.5

RED

0.5

RED

0.5

GRN

0.5

RED

Manifold

Absolute

Pressure

(MAP)

Sensor

F10 B2

0.5

GRN

B7 A3

5 Volt

Reference

Signal

MAP Sensor

Input

Sensor

Ground

0.75

AB C

Intake

Air Temperature

Sensor

Throttle Position

Sensor

Engine

Control

Module

(ECM)

HI OUT LO

0.5

CIRCUIT DESCRIPTION

The manifold absolute pressure (MAP) sensor

responds to changes in intake manifold pressure.

The MAP sensor signal voltage to the engine control

module (ECM) varies from below 2 volts at idle (low

manifold pressure) to above 4 volts with the ignition

ON engine not running or at wide-open throttle (high

manifold pressure).

A "speed density" method of determining engine

load is used. This is calculated using inputs from the

MAP sensor, the CKP Sensor, and the Intake Air

Temperature (IAT) sensor. The MAP sensor is the

main sensor used in this calculation, and measuring

engine load is its main function. The ECM monitors

the MAP signals for voltages outside the normal

range (10-104 kpa) of the MAP sensor. If the ECM

detects a MAP signal voltage that is excessively low,

Diagnostic Trouble Code 34 will be set.

CONDITIO NS FOR SETTING THE DTC

• Manifold Absolute Pressure is less than 14 kpa

and one of following condition is met the DTC will

set.

Condition A:

• Malfunction 21 not pr esent and rpm is les s than

1050.

Or,

Condition B:

• Malfunction 21 not present and rpm is greater

than 1050 and TP opening is greater than

18.75% and ignition ON.

ACTIO N TAKEN WHEN THE DTC SETS

• The ECM will illuminate the malfunction indicator

lamp (MIL).

CONDITIONS FOR CLEARING THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear

them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness - Inspect the wiring harness for

damage, shorts to Ground, shorts to Battery

positive, and Open circuits. If the harness appears

to be OK, observe the MAP display on the Scan

Tool while moving connectors and wiring

harnesses related to the sensor. A change in the

display will indicate the location of the fault.

• A faulty 5 volt reference circuit could also set a TP

Sensor Diagnostic Trouble Code because the two

sensors share the same 5 volt reference pin at the

ECM.

DTC (FLASH DTC = 34) MANIFOLD ABSOLUTE PRESSURE (MAP) TOO LOW

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System

Check" performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition ON engine OFF.

2. With the throttle closed, observe the MAP value displayed on

the Scan Tool.

Is the MAP value near the specified value?

10.3 kPa

at sea level Go to Step 4 Go to Step 3

1. Ignition ON, engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

34.

Does the Scan Tool indicate Diagnostic Trouble Code 34 failed? -

Go to Step 4

Refer to

Diagnostic

Aids

1. Ignition OFF.

2. Disconnect the MAP sensor electrical connector.

3. Jumper the 5 volt reference circuit and the MAP signal

together at the MAP sensor harness connector.

4. Ignition ON.

5. Observe the MAP value displayed on the Scan Tool.

Is the MAP value near the specified value? 5V

104 kPa Go to Step 10 Go to Step 5

1. Disconnect the jumper.

2. Connect a test light between B+ and the MAP sensor signal

circuit at the MAP sensor harness connector.

3. Observe the MAP value displayed on the Scan Tool.

Is the MAP value near the specified value? 5V

104 kPa Go to Step 6 Go to Step 8

STEP ACTION VALUE(S) YES NO

1. Ignition OFF.

2. Disconnect the ECM and check the 5 volt reference circuit

for an open or short to ground.

3. If the 5 volt reference circuit is open or shorted to ground,

repair it as necessary.

Was the 5 volt reference circuit open or shorted to ground?

Verify repair Go to Step 7

7Check the 5 volt reference circuit for a poor connection at the

ECM and replace the terminal if necessary.

Did the terminal require replacement? -

Verify repair Go to Step 11

1. Ignition OFF.

2. Disconnect the ECM, and check the MAP signal circuit for an

open,short to ground, or short to the sensor ground circuit.

3. If the MAP sensor signal circuit is open or shorted to ground,

repair it as necessary.

Was the MAP signal circuit open or shorted to ground?

Verify repair Go to Step 9

Check the MAP sensor signal circuit for a poor connection at the

ECM and the MAP sensor; replace the terminal if necessary.

Did the terminal require replacement? -

Verify repair Go to Step 11

10 Replace the MAP sensor.

Is the action complete? -Verify repair -

11 Replace the EPROM or ECM. Note) Refer to 6E1-243.

Is the action complete? -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 49)

SYSTEM VOLTAGE HIGH

HOT AT ALL TIMES

Ignition

Coil

Fuse

15A

I/P

FUSE

BLOCK

Engine

Control

Module

(ECM)

HOT AT ALL TIMES

ECM

Fuse

15A

U/H

FUSE

BLOCK

1.25

RED/

WHT

1.25

BLK

1.25

BLK

W/G

1.25

RED/

WHT

A4 A5

Batt+

Ignition

Coil

A13

0.5

G/W

E3 E2 E4

Ignition Feeds

1,4 2,3

Relay

Fuel

Pump

ECM

Fuse

15A

F/Pump

Fuse

20A

CIRCUIT DESCRIPTION

The engine control module (ECM) monitors the

system voltage on the ignition feed terminal to the

ECM. A system voltage Diagnostic Trouble Code will

set whenever the voltage is above a calibrated value.

This malfunction detects an over-voltage condition in

the battery voltage circuit.

CONDITIO NS FOR SETTING THE DTC

•Engine is running.

•Battery Voltage is greater than 17.2V.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) for the first time the malfunction is

detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•Check for a faulty charging system components.

DTC (FLASH DTC = 49) SYSTEM VOLTAGE HIGH

STEP ACTION VALUE(

S) YES NO

1 Was the "On-Board Diagnostic (OBD) System Check"

performed? -Go to Step 2

Go to OBD

System Check

1. Ignition OFF, engine OFF.

2. Using a Digital Voltmeter (DVM), measure the battery

voltage at the battery.

Is the battery voltage greater than the specified va lue? 16V Go to Step 3 Go to Step 4.

1. Charge the battery and clean the battery terminals.

2. Clean the battery ground cable connection if corrosion is

indicated.

Is the battery voltage greater than the specified va lue? 16V Replace battery Go to Step 4

1. Turn OFF all the accessories.

2. Install the Scan Tool.

3. Select the ignition voltage parameter on the data list.

4. Start the engine and raise the engine speed to 2000 RPM.

Is it the voltage above the specified value? 16V Go to Step 5 Go to Step 6

5Replace or repair the generator (see Charging System).

Is a malfunction present? -Verify Repair -

6Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify Repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 69)

INTAKE AIR TEMPERATURE (I AT) SENSOR TOO HIGH

0.5

G0.5

YEL/

GRN

Engine

Control

Module

(ECM)

A3 F10

IAT

Sensor

Input

Sensor

Ground

Intake Air

Temperature

(IAT)

Sensor

MAP

Sensor

CIRCUIT DESCRIPTION

The intake air temperature (IAT) sensor is a thermistor

which measures the temperature of the air entering

the engine. The engine control module (ECM) applies

5 volts through a pull-up resistor to the IAT sensor.

When the intake air is cold, the sensor resistance is

high and the ECM will monitor a high signal voltage on

the IAT signal circuit. If the intake air is warm, the

sensor resistance is lower, causing the ECM to

monitor a lower voltage. Diagnostic Trouble Code 69

will set when the ECM detects an excessively high

signal voltage on the intake air temperature sensor

signal circuit.

CONDITIO NS FOR SETTING THE DTC

•The engine is running.

•IAT sensor temperature is greater than 140 degC.

The above conditions are met.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

•The ECM will use a default IAT value based on

ECM inputs and engine run time.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

•Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

•Damaged harness - Inspect the wiring harness for

damage, shorts to Ground, shorts to Battery

Positive, and Open Circuits. If the harness appears

to be OK, observe the IAT display on the Sc an T ool

while moving connectors and wiring harnesses

related to the IAT sensor. A change in the IAT

display will indicate the location of the fault.

If Diagnostic Trouble Code 69 cannot be duplicated,

the information included in the Failure Records data

can be useful in determining vehicle mileage since the

Diagnostic Trouble Code was last set.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. Verifies that the fault is present.

3. If Diagnostic Trouble Code 69 can be repeated

only by duplicating the Failure Records conditions,

refer to the "Temperature vs. Resistance Values"

table. The table may be used to test the IAT s ens or

at various temperatures to evaluate the possibility

of a "shifted" sensor that may be open above or

below a certain temperature. If this is the case,

replace the IAT sensor. If the IAT sensor appears

to be OK, the fault is intermittent; refer to

Diagnostic Aids.

INTAKE AIR TEMPERATURE SENSOR

°C °F OHMS

Temperature vs. Resistance Values

(approximate)

100 212 177

80 176 332

60 140 667

45 113 1188

35 95 1802

25 77 2796

15 59 4450

5 41 7280

−5 23 12300

−15 5 21450

−30 −22 52700

−40 −40 100700

DTC (FLASH DTC = 69) INTAKE AIR TEMPERATURE (IAT) SENSOR TOO HIGH

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Ignition ON, engine OFF Observe the "Intake Air Temp" values

displayed on the Scan Tool.

Is the "Intake Air Temp" values below the specified value?

−36°C

(−32.8°F) Go to Step 4 Go to Step 3

1. Ignition ON, engine OFF.

2. Using a Scan Tool, monitor info for Diagnostic Trouble Code

69.

Does the Scan Tool indicate Diagnostic Trouble Code 69 failed? -

Refer to Test

Description

Refer to

Diagnostic

Aids

1. Ignition OFF.

2. Disconnect the IAT sensor electrical connector.

3. Jumper the IAT signal circuit and the sensor ground circuit

together at the IAT sensor harness connector.

4. Ignition ON.

5. Observe the "Intake Air Temp" values displayed on the

Scan Tool.

Is the "Intake Air Tempe" values at the specified value?

140°C

(284°F) Go to Step 6 Go to Step 5

1. Jumper the IAT signal circuit at the IAT sensor harness

connector to chassis ground.

2. Observe the "Intake Air Temp" display on the Scan Tool.

Is the "Intake Air Tempe" at the specified value? 0V

140°C

(284°F) Go to Step 7 Go to Step 8

6Check for poor connections at the IAT sensor and replace

terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 10

1. Ignition OFF.

2. Disconnect the ECM, and check the IAT sensor ground

circuit for an open.

3. If the IAT sensor ground circuit is open, repair it as

necessary.

Was the IAT sensor ground circuit open?

Verify repair Go to Step 9

1. Ignition OFF.

2. Disconnect the ECM, and check the IAT signal circuit for an

open.

3. If the IAT sensor signal circuit is open, repair it as necessary.

Was the IAT signal circuit open?

Verify repair Go to Step 9

Check for a poor sensor ground or IAT signal circuit terminal

connection at the ECM and replace terminal(s) if necessary.

Did any of the terminal need to be replaced? -

Verify repair Go to Step 11

10 Replace the IAT sensor.

Is the action complete? -Verify repair -

11 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 71)

INTAKE AIR TEMPERATURE (I AT) SENSOR TOO LOW

0.5

G0.5

YEL/

GRN

Engine

Control

Module

(ECM)

A3 F10

IAT

Sensor

Input

Sensor

Ground

Intake Air

Temperature

(IAT)

Sensor

MAP

Sensor

CIRCUIT DESCRIPTION

The intake air temperature (IAT) sensor is a thermistor

which measures the temperature of the air entering

the engine. The engine control module (ECM) applies

5 volts through a pull-up resistor to the IAT sensor.

When the intake air is cold, the sensor resistance is

high and the ECM will monitor a high signal voltage on

the IAT signal circuit. If the intake air is warm, the

sensor resistance is lower, causing the ECM to

monitor a lower voltage. Diagnostic Trouble Code 71

will set when the ECM detects an excessively low

signal voltage (short to ground) on the intake air

temperature sensor signal circuit.

CONDITIO NS FOR SETTING THE DTC

•The engine has been running for over 2 minutes.

•IAT sensor temperature is less than −36 degC.

The above conditions are met.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL).

•The ECM will use a default IAT value based on

PCM inputs and engine run time.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

•Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

•Damaged harness - Inspect the wiring harness for

damage, shorts to ground, shorts to battery, and

open circuits. If the harness appears to be OK,

observe the IAT display on the Scan Tool while

moving connectors and wiring harnesses related to

the IAT sensor. A change in the IAT display will

indicate the location of the fault.

If Diagnostic Trouble Code 71 cannot be duplicated,

the information included in the Failure Records data

can be useful in determining vehicle mileage since the

Diagnostic Trouble Code was last set.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart:

2. Verifies that the fault is present.

3. If Diagnostic Trouble Code 71 can be repeated

only by duplicating the Failure Records condition,

refer to the Temperature vs. Resistance Value

table. The table may be used to test the IAT s ens or

at various temperatures to evaluate the possibility

of a "shifted" sensor that m ay be stored above or

below a certain temperature. If this is the case,

replace the IAT sensor. If the IAT sensor appears

to be OK, the fault is intermittent; refer to

Diagnostic Aids.

INTAKE AIR TEMPERATURE SENSOR

°C °F OHMS

Temperature vs. Resistance Values

(approximate)

100 212 177

80 176 332

60 140 667

45 113 1188

35 95 1802

25 77 2796

15 59 4450

5 41 7280

−5 23 12300

−15 5 21450

−30 −22 52700

−40 −40 100700

DTC (FLASH DTC = 71) INTAKE AIR TEMPERATURE (IAT) SENSOR TOO LOW

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition ON, engine OFF

2. Using a Scan Tool, monitor the intake air temperature (IAT).

Is the intake air temperature greater then the specified value? 140°C

(284°F) Go to Step 4 Go to Step 3

1. Ignition ON, engine OFF Review and record Scan Tool

Failure Records data.

2. Using a Scan Tool, monitor the info for Diagnostic Trouble

Code 71.

Does the Scan Tool indicate Diagnostic Trouble Code 71?

Refer to Test

Description

Refer to

Diagnostic

Aids

1. Ignition OFF.

2. Disconnect the IAT sensor electrical connector.

3. Ignition ON.

4. Observe the intake air temperature on the Scan Tool.

Is the intake air temperature below the specified value? −36°C

(−32.8°F) Go to Step 6 Go to Step 5

1. Ignition OFF.

2. Disconnect the PCM electrical connectors.

3. Check the IAT sensor signal circuit for a short to ground.

Is the IAT sensor signal circuit shorted to ground? -

Verify repair Go to Step 7

6Replace the IAT sensor.

Is the action complete? -Verify repair -

7Replace the EPROM or ECM. Note) Refer to 6E1-243.

Is the action complete? -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 17)

INJECTOR CIRCUIT M ALFUNCTION

ECM

Fuse

15A

Engine

Fuse

15A

Canister

Purge

Solenoid

1.25

R/W

0.85G/W

2B/R

0.85G/R

0.85G/B

0.85G

1.25

R/W

0.85

L/Y

Injector

Fuse

20A

Fuel

Pump

A4A6 A8 A9 A7 A5 E16

Fuel

Injector

Control

Engine

Control

Module

(ECM)

HOT AT ALL TIMES HOT IN RUN AND START

CIRCUIT DESCRIPTION

The engine control module (ECM) has 2 injector driver

circuits. Each controls 2 injectors as a one group.

When a driver circuit is grounded by the ECM, the

injector is activated. The ECM monitors the current in

each driver circuit. The ECM measures a voltage drop

through a fixed resistor and controls it. The voltage on

each driver is monitored to detect a fault. If the voltage

is not what the ECM expects to monitor on the circuit,

a Diagnostic Trouble Code is set. This Diagnostic

Trouble Code is also set if an injector driver is shorted

to voltage. This code an injectors short to ground,

battery or a disconnected injector, then a DTC 17 will

be set.

CONDITIO NS FOR SETTING THE DTC

•The actual output voltage of injector driver is

opposite to the expected state thus setting injector

feedback line low.

•Fuel pump relay is commanded on and Fuel pump

relay is not shorted to bettery and battery voltage is

greater than 9 volts.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL).

•"Open Loop" fuel control will be in effect.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

An injector driver circuit that is open or shorted to

voltage will cause a Diagnostic Trouble Code 17 to

set. It will also cause a misfire due to an inoperative

injector.

Long term and short term fuel trims that are

excessively high or low are a good indication that an

injector is faulty. Use Fuel Injector Coil Test Procedure

to check for faulty injectors.

TEST DESCRIPTION

The number(s) below refer to the step number(s) on

the Diagnostic Chart.

3. This step determines if Diagnostic Trouble Code 17

is the result of a hard failure or an intermittent

condition.

4. This steps tests the harness wiring and ECM

control of the injectors.

6. Because the test light was ON steady, voltage to

the injector is OK, but the driver circuit is grounded

at all times. This step determines if the circuit is

shorted to ground or the ECM is faulty.

8. Because the test light was OFF steady, the injector

driver circuit is shorted to voltage.

10.Normal injector resistance is slightly more than if

tested directly at the injector because it includes

resistance of the harness wires. The normal value

is about 13.5Ω.

DTC (FLASH DTC = 17) INJECTOR CIRCUIT MALFUNCTION

(REPEAT FOLLOWING STEPS FOR EACH INJECTOR IF NECESSARY)

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Will the engine start?

-Go to Step 3

Cranks But

Will Not Run

Chart

31. Install the Scan Tool.

2. Idle the engine for one minute.

Does the Diagnostic Trouble Code 17 Set? -

Go to Step 4

Go to

Diagnostic

Aids

1. Ignition off.

2. Disconnect the injector connector of No.1 Cyl. And then start

the engine to check the injector working condition.

3. Repeat above steps on all injectors.

4. If the injector and injector driver circuit is normal condition,

the engine becomes rough running.

Does the engine running condition change?

Go to OBD

System Check

Go to Step 5

5Does the engine Idle Condition change?

Note the detected faulty injector. -Go to Step 6 Go to Step 8

1. Ignition off.

2. Disconnect the ECM connector for the affected injectors.

3. With a test light (commercial available) connected to B+,

probe the affected applicable injector circuit.

Does the test light illuminate?

Go to Step 7 Go to Step 8

STEP ACTION VALUE(S) YES NO

7Repair short to ground in the injector driver circuit.

Is the action complete? - Verify Repair -

Re-connect the ECM connector.

1. Disconnect the injector test connector.

2. Ignition ON.

3. Use a test light (commercial available)

connected to ground to probe the injector connector

terminal.

4. Only the Ign+ terminal should illuminate the test high.

Besides the Ign+, did any other terminal illuminate the test light?

Go to Step 9 Go to Step 10

9 Repair the short to voltage in the injector driver circuit. - Verify Repair Go to Step 10

1. Ignition OFF.

2. Disconnect the ECM connector.

3. Clip one lead of an ohmmeter to the ignition pin on the

harness side ECM connector.

4. Touch the other lead to the another pin in that connector.

Instead of normal injector resistance, did the ohmmeter indicate

an open circuit?

Go to Step 11 Go to Step 12

11 Repair the open circuit or open injector. - Verify Repair Go to Step 12

12 Replace the *EPROM or ECM. Note) *Refer to 6E1-243. - Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 41)

IGNI TI ON COIL DRIVER "B" SHORT TO BATTERY

HOT IN START AND RUN

IG.

Coil

Fuse

15A

I/P

FUSE

BLOCK

W/G

Ignition

Coil

Ignition

Coil

1.25

Engine

Control

Module

(ECM)

E1 E4 E3

Electronic Spark

Timing Control

1.25

BLK

1.25

BLK

1,4 2,3

CIRCUIT DESCRIPTION

The ignition control circuit in ECM provides a zero volt

or a 5 volt signal to the ignition coil driver. The normal

circuit voltage is zero volts. When the coil driver

receives the 5 volt signal from the ignition control

circuit, it provides a ground path for the B+ voltage

supplied to the ignition primary coil. When the ECM

turns off the 5 volts to the module, the module will

remove the ground path of the ignition primary coils;

causing the magnetic field produces a voltage in the

secondary coils which fires the spark plug.

The circuit between the coil driver and the ignition

control circuit is monitored for a short to battery on the

Electronic Spark Timing B/coil driver B line. When the

ECM detects a problem in the ignition control circuit, it

will set DTC 41.

CONDITIO NS FOR SETTING THE DTC

•Fault feedback line generates an interrupt on start

of dwell.

•No Electronic Spark Timing actiration requested by

serial data.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at the ECM - Inspect the harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connections.

• Damaged harness - Inspect the wiring harness for

damage; Open circuits, shorts to ground, or shorts

to Voltage. If the harness appears to be OK,

observe the Scan Tool display related to DTC 41

while moving the connector and wiring related to the

ignition system. A change in the display will indicate

the location of the fault.

• This code detects a short to battery on the

Electronic Spark Timing B/Coil Driver B (#2, #3 cyl.)

line.

DTC (FLASH DTC = 41) IGNITION COIL DRIVER "B" SHORT TO BATTERY

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Check for a faulty connection or damaged terminals at the

ignition coil.

Was a problem found? -

Verify repair Go to Step 3

3Check for a faulty connection or damaged terminals at the ECM

connector.

Was a problem found? -

Verify repair Go to Step 4

1. Ignition OFF.

2. Disconnect the ignition coil.

3. Check the ignition coil circuit for a short to battery.

Was a problem found?

Verify repair Go to Step 5

5Check for a short circuit between the ignition coil and the ECM.

If a problem is found, repair the wire harness.

Is there still a problem? -

Verify repair Go to Step 6

6Replace the ignition control module.

Verify repair.

Is there still a problem? -

Go to Step 8

7Replace the EPROM or ECM.

Is the repair complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 42)

IGNI TI ON COIL DRIVER "A" SHORT TO BATTERY

HOT IN START AND RUN

IG.

Coil

Fuse

15A

I/P

FUSE

BLOCK

W/G

Ignition

Coil

Ignition

Coil

1.25

Engine

Control

Module

(ECM)

E1 E4 E3

Electronic Spark

Timing Control

1.25

BLK

1.25

BLK

1,4 2,3

CIRCUIT DESCRIPTION

The ignition control circuit in ECM provides a zero volt

or a 5 volt signal to the ignition coil driver. The normal

circuit voltage is zero volts. When the module receives

the 5 volt signal from the ignition control circuit, it

provides a ground path for the B+ voltage supplied to

the ignition primary coil. When the ECM turns off the 5

volts to the module, the module will remove the

ground path of the ignition primary coils; causing the

magnetic field produces a voltage in the secondary

coils which fires the spark plug.

The circuit between the coil driver and the ignition

control circuit is monitored for a short to battery on the

Electronic Spark Timing A/coil driver A line. When the

ECM detects a problem in the ignition control circuit, it

will set DTC 42.

CONDITIO NS FOR SETTING THE DTC

•Fault feedback line generates an interrupt on start

of dwell.

•No Electronic Spark Timing requested by serial

data.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at the ECM - Inspect the harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connections.

• Damaged harness - Inspect the wiring harness for

damage; Open circuits, shorts to ground, or shorts

to Voltage. If the harness appears to be OK,

observe the Scan Tool display related to DTC 42

while moving the connector and wiring related to the

ignition system. A change in the display will indicate

the location of the fault.

• This code detects a short to battery on the

Electronic Spark Timing A/Coil Driver A (#1, #4 cyl.)

line.

DTC (FLASH DTC = 42) IGNITION COIL DRIVER "A" SHORT TO BATTERY

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Check for a faulty connection or damaged terminals at the

ignition coil.

Was a problem found? -

Verify repair Go to Step 3

3Check for a faulty connection or damaged terminals at the ECM

connector.

Was a problem found? -

Verify repair Go to Step 4

1. Ignition OFF.

2. Disconnect the ignition coil.

3. Check the ignition coil circuit for a short to battery.

Was a problem found?

Verify repair Go to Step 5

Check for a short circuit between the ignition coil and the ECM.

If a problem is found, repair the wire harness.

Is there still a problem? -

Verify repair Go to Step 6

6Replace the ignition control module.

Verify repair.

Is there still a problem? --

Go to Step 7

7Replace the EPROM or ECM.

Is the repair complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 63)

IGNITION COIL DRIVER "B" SHORT TO GROUND

HOT IN START AND RUN

IG.

Coil

Fuse

15A

I/P

FUSE

BLOCK

W/G

Ignition

Coil

Ignition

Coil

1.25

Engine

Control

Module

(ECM)

E1 E4 E3

Electronic Spark

Timing Control

1.25

BLK

1.25

BLK

1,4 2,3

CIRCUIT DESCRIPTION

The ignition control circuit provides a zero volt or a 5

volt signal to the ignition coil driver. The normal circuit

voltage is zero volts. When the module receives the 5

volt signal from the engine control module (ECM), it

provides a ground path for the B+ voltage supplied to

the ignition primary coil. When the ECM turns off the 5

volts to the module, the module will remove the

ground path of the ignition primary coils; causing the

magnetic field produces a voltage in the secondary

coils which fires the spark plug.

The circuit between the ECM and the ignition control

module is monitored for a short to ground on the

Electronic Spark Timing B/coil driver B line. When the

ECM detects a problem in the ignition control circuit, it

will set DTC 63.

CONDITIO NS FOR SETTING THE DTC

•Fault feedbac k line gener ates an interr upt on end of

dwell.

•No Electronic Spark T iming activation reguested by

serial data.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at the ECM - Inspect the harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connections.

• Damaged harness - Inspect the wiring harness for

damage; Open circuits, shorts to ground, or shorts

to Voltage. If the harness appears to be OK,

observe the Scan Tool display related to DTC 63

while moving the connector and wiring related to the

ignition system. A change in the display will indicate

the location of the fault.

• This code detects a short to ground on the

Electronic Spark Timing B/coil Driver B(#2, #3 cyl.)

line.

DTC (FLASH DTC = 63) IGNITION COIL DRIVER "B" SHORT TO GROUND

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Check for a faulty connection or damaged terminals at the

ignition control module.

Was a problem found? -

Verify repair Go to Step 3

3Check for a faulty connection or damaged terminals at the ECM

connector.

Was a problem found? -

Verify repair Go to Step 4

Check for an open circuit between the ignition coil and ECM.

If a problem is found, repair the wire harness.

Is there still a problem? -

Verify repair Go to Step 5

Check for an short to ground between the ignition coil and

battery +.

If a problem is found, repair the wire harness.

Is there still a problem?

Verify repair Go to Step 6

1. Ignition OFF.

2. Disconnect the ignition coil.

3. Check for an open circuit in the ignition coil.

Was a problem found?

Verify repair Go to Step 5

7Replace the ignition coil.

Verify repair.

Is there still a problem? -

Go to Step 8

8Replace the EPROM or ECM.

Is the repair complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 64)

IGNITION COIL DRIVER "A" SHORT TO GROUND

HOT IN START AND RUN

IG.

Coil

Fuse

15A

I/P

FUSE

BLOCK

W/G

Ignition

Coil

Ignition

Coil

1.25

Engine

Control

Module

(ECM)

E1 E4 E3

Electronic Spark

Timing Control

1.25

BLK

1.25

BLK

1,4 2,3

CIRCUIT DESCRIPTION

The ignition control circuit in ECM provides a zero volt

or a 5 volt signal to the ignition coil driver. The normal

circuit voltage is zero volts. When the coil driver

receives the 5 volt signal from the ignition control

circuit, it provides a ground path for the B+ voltage

supplied to the ignition primary coil. When the ECM

turns off the 5 volts to the module, the module will

remove the ground path of the ignition primary coils;

causing the magnetic field produces a voltage in the

secondary coils which fires the spark plug.

The circuit between the coil driver and the ignition

control circuit is monitored for a short to ground on the

Electronic Spark Timing A/coil drive A line. When the

ECM detects a problem in the ignition control circuit, it

will set DTC 64.

CONDITIO NS FOR SETTING THE DTC

•Fault feedbac k line gener ates an interr upt on end of

dwell.

•No Electronic Spark T iming activation requested by

serial data.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the fault is detected.

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at the ECM - Inspect the harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connections.

• Damaged harness - Inspect the wiring harness for

damage; Open circuits, shorts to ground, or shorts

to Voltage. If the harness appears to be OK,

observe the Scan Tool display related to DTC 64

while moving the connector and wiring related to the

ignition system. A change in the display will indicate

the location of the fault.

• This code detects a short to ground on the

Electronic Spark Timing A/Coil Driver A (#1, #4 cyl.)

line.

DTC (FLASH DTC = 64) IGNITION COIL DRIVER "A" SHORT TO GROUND

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Check for a faulty connection or damaged terminals at the

ignition control module.

Was a problem found? -

Verify repair Go to Step 3

3Check for a faulty connection or damaged terminals at the ECM

connector.

Was a problem found? -

Verify repair Go to Step 4

Check for a open circuit between the ignition coil and ECM.

If a problem is found, repair the wire harness.

Is there still a problem? -

Verify repair Go to Step 5

Check for a short to ground between the ignition coil and battery

If a problem is found, repair the wire harness.

Is there still a problem?

Verify repair Go to Step 6

1. Ignition OFF.

2. Disconnect the ignition coil.

3. Check the ignition control circuit for a short to voltage.

Was a problem found?

Verify repair Go to Step 7

7Replace the ignition control module.

Verify repair.

Is there still a problem? -

Go to Step 8

8Replace the EPROM or ECM.

Is the repair complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 35)

IDLE AI R CONTROL (IAC) ERROR

Engine

Control

Module

(ECM)

B16

0.5

L/W

0.5

L/R

Idle Air

Control

(IAC)

Valve

0.5

L/B

B15

DCBA

B13 B14

IAC

High

IAC

Low

IAC

High

IAC

Low

A B

CIRCUIT DESCRIPTION

The engine control module (ECM) controls engine idle

speed with the idle air control (IAC) valve. To increase

idle speed, the ECM retracts the IAC valve pintle away

from its seat, allowing more air to bypass the throttle

bore. To decrease idle speed, it extends the IAC valve

pintle towards its seat, reducing bypass air flow. A

Scan Tool will read the ECM commands to the IAC

valve in counts. Higher counts indicate more air

bypass (higher idle). Lower counts indicate less air is

allowed to bypass (lower idle).

This malfunction detects an error in the IAC control

logic, then DTC 35 will set.

CONDITIO NS FOR SETTING THE DTC

•Engine rpm error is greater than 175 rpm.

•No DTC 21, 22 and 24 present.

And,

•Engine desired rpm is not fixed by tester.

•IAC movement is not inhibited by low or high battery

voltage.

And,

•IAC normal closed loop is enabled.

•Coolant of lesets are decayed to 0.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL).

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

A slow, unstable, or fast idle may be caused by a non-

IAC system problem that cannot be overcome by the

IAC valve. Out of control range IAC Scan Tool counts

will be above 60 if idle is too low, and zero counts if

idle is too high. The following checks should be made

to repair a non-IAC system problem:

•Vacuum leak (high idle) - If idle is too high, stop the

engine. Fully extend (low) IAC with the IAC motor

analyzer 5-8840-2312-0. Start the engine. If idle

speed is above 825 RPM, locate and correct the

vacuum leak, including the PCV system. Check for

binding of the throttle blade or linkage.

Following are applicable to the vehicle with

closed Loop System.

•Throttle body - Remove the IAC valve and inspect

the bore for foreign material.

•IAC valve electrical connections - IAC valve

connections should be carefully checked for proper

contact.

•PCV hose - An incor r ec t or faulty hose may result in

an incorrect idle s peed. Ref er to Diagnosis, Rough

Idle, Stalling. If intermittent poor driveability or idle

symptoms are resolved by disconnecting the IAC,

carefully recheck the connections and valve

terminal resistance, or replace the IAC.

•Lean heated oxygen sensor signal (high air/fuel

ratio) - The idle speed may be too high or too low.

Engine speed may vary up and down, and

disconnecting the IAC valve does not help.

Diagnostic trouble code 44 may be set. Scan Tool

oxygen (O2) voltage will be less than 27 mV (2.74

V). Check for low regulated fuel pressure, waterin

fuel, or a restricted injector.

•Rich heated oxygen sens or signal ( low air/fuel ratio)

- The idle speed will be too low. Scan Tool IAC

counts will usually be above 80. The system is

obviously rich and may exhibit black smoke in the

exhaust.

•Scan T ool O2 voltage will be fixed at about 750 m V

(0.75 V). Check for high fuel pressure, or a leaking

or sticking injector. A silicon-contaminated heated

oxygen sensor will show an O2 voltage slow to

respond on the Scan Tool.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

1. The IAC motor analyzer 5-8840-2312-0 is used to

extend and retract the IAC valve. Valve movement

is verified by an engine speed change. If no

change in engine speed occurs, the valve can be

resettled when removed from the throttle body.

2. This step checks the quality of the IAC movement

in step 1. Between 700 revolutions per minute

(RPM) and about 1500 RPM, the engine speed

should change smoothly with each flash of the

tester light in both extend and retract. If the IAC

valve is retracted beyond the control range (about

1500 RPM), it m ay take m any flashes to ex tend the

IAC valve before engine speed will begin to drop.

This is normal on certain engines. Fully extending

the IAC may cause engine stall. This may be

normal.

6. Steps 1 and 2 verified the proper IAC valve

operation. This step checks the IAC circuits. Each

lamp on the noid light should flash red and green

while the IAC valve is cycled. While the sequence

of color is not important, if either light is OFF or

does not flas h red and green, check the circuits for

faults, beginning with poor terminal contacts.

DTC (FLASH DTC = 35) I DLE AIR CONTROL (IAC) ERROR

STEP ACTION VALUE(S) YES NO

1. Ignition OFF..

2. Connect the IAC motor analyze r 5-8840-2312-0 to the IAC

valve.

3. Set the parking brake.

4. Block the wheels.

5. Turn the air conditioning OFF.

6. Idle the engine in Park (A/T) or Neutral (M/T).

7. Install the scan tool. Display the RPM.

8. Use the IAC motor analyzer 5-8840-2312-0 to extend and

retract the IAC valve.

9. The engine speed should decrease and increase as the IAC

is cycled.

Does the RPM change?

Go to Step 2 Go to Step 3

2RPM should change smoothly with each flash of the IAC motor

analyzer 5-8840-2312-0 light.

Does the RPM change within the range specified? 700-1500

RPM Go to Step 6 Go to Step 3

3Check the IAC passages.

Are the IAC passages blocked? -Go to Step 4 Go to Step 5

4Clear any obstruction from the IAC passages.

Is the action complete? -Verify repair -

5Replace the IAC. Refer to On-Vehicle Service, Idle Air Control

Valve.

Is the action complete? -

Verify repair

1. Install the appropriate IAC noid light from 5-8840-2312-0 into

the powertrain control module harness.

2. Cycle the IAC motor analyzer 5-8840-2312-0 and observe

the noid lights.

3. Both the lights should cycle red and green, but never OFF,

as the RPM is changed over its range.

Do the noid lights cycle red and green?

Go to Step 7 Go to Step 8

1. Use the other connector on the IAC motor analyzer 5-8840-

2312-0 pigtail.

2. Check the resistance across the IAC coils.

Measure the resistance between terminal A and terminal B.

3. Measure the resistance between terminal C and terminal D.

Is the resistance within the specified range?

40-80 ohms Go to Step 9 Go to Step 10

If the circuits did not test green and red, check the following:

•Faulty connector terminal contacts.

•Open circuits, including connections.

•Circuits shorted to ground or voltage.

•Faulty engine control module connector(s) or engine control

module.

Are repairs necessary?

Go to Step 13

STEP ACTION VALUE(S) YES NO

1. Check the resistance between the IAC terminal B and

terminal C.

2. Check the resistance between the IAC terminal A and

terminal D.

Is the resistance infinite?

Go to Step 11 Go to Step 12

10 Replace the IAC. Refer to On-Vehicle Service, Idle Air Control

Valve.

Is the action complete? -

Go to Step 7

11 Check the IAC valve and circuit.

Are the IAC valve and circuit OK? - Refer to

Diagnostic

Aids Go to Step 12

12 Replace the IAC. Refer to On-Vehicle Service, Idle Air Control

Valve.

Is the action complete?

-Go to Step 9 -

13 Repair or replace the faulty component(s).

Is the action complete? -Go to Step 6 -

DIAG NOSTI C TROUBLE CODE (DTC) 56 (FLASH DTC = 56)

CHECK ENGINE LAMP LOW ERROR

HOT AT ALL TIMES

ECM

Fuse

15A

U/H

FUSE

BLOCK

HOT IN START AND RUN

Meter

Fuse

15A

I/P

FUSE

BLOCK

Malfuntion

Indicator

Lamp

0.85

YEL

1.25

RED/

WHT

1.25

RED/

WHT

0.5

BR/Y

Instrument

Panel(I/P)

Cluster

Engine

Control

Module

(ECM)

A4 A5 B4

Batt+ Malfunction

Indicator

Lamp

Control

TACHO

CIRCUIT DESCRIPTION

The “Check Engine” lamp (MIL) should always be

illuminated and steady with the ignition ON and the

engine stopped. Battery feed Voltage is supplied to the

MIL bulb through the meter fuse. The engine control

module (ECM) turns the MIL ON by grounding the MIL

driver circuit.

CONDITIO NS FOR SETTING THE DTC

•This code detects a low impedanc e short to ground

on an open contact on the MIL output.

•Driver f eedback infor m ation shows a low state at its

operation even when commanded high.

ACTIO N TAKEN WHEN THE DTC SETS

•The MIL will not turn ON.

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

An intermittent MIL may be caused by a poor

connection, rubbed-through wire insulation, or a wire

broken inside the insulation. Check for the following

items:

• Inspect the ECM harness and connections for

improper mating, broken locks, improperly formed

or damaged terminals, poor terminal-to-wire

connection, and damaged harness.

• If the engine runs OK, check for a faulty light bulb,

an open in the MIL driver circuit, or an open in the

instrument cluster ignition feed.

• If the engine cranks but will not run, check for an

open ECM ignition or battery feed, or a poor ECM to

engine ground.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. A “No MIL” condition accompanied by a no-start

condition suggests a faulty ECM ignition feed or

battery feed circuit.

9. Using a test light connected to B+, probe each of

the ECM ground terminals to ensure that a good

ground is present. Refer to ECM Terminal End

View for terminal locations of the ECM ground

circuits.

DTC (FLASH DTC = 56) CHECK ENGINE LAMP LOW ERROR

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

2Attempt to start the engine.

Does the engine start? -Go to Step 3 Go to Step 6

3Check the meter fuse for the instrument cluster turn, back and

gauge.

Is the fuse OK? -

Go to Step 4 Go to Step 16

1. Ignition OFF.

2. Disconnect the ECM.

3. Jumper the MIL driver circuit at the ECM connector to

ground.

4. Ignition ON.

Is the MIL ON?

Go to Step 10 Go to Step 11

6Check the ECM ignition feed and battery feed fuses

(15A Ignition fuse and 15A ECM fuse).

Are both fuses OK? -

Go to Step 8 Go to Step 15

8Probe the battery feed circuit at the ECM harness connector

with a test light to ground.

Is the test light ON? -

Go to Step 9 Go to Step 14

9Check for a faulty ECM ground connection.

Was a problem found? -Verify repair Go to Step 10

STEP ACTION VALUE(S) YES NO

10 Check for damaged terminals at the ECM.

Was a problem found? -Verify repair Go to Step 17

11 Check for an open MIL driver circuit between the ECM and the

MIL.

Was a problem found? -

Verify repair Go to Step 18

14 Locate and repair the open ECM battery feed circuit.

Is the action complete? -Verify repair -

15 Locate and repair the short to ground in the ECM battery feed

circuit.

Is the action complete? -

Verify repair

16 Locate and repair the short to ground in the MIL feed circuit to

the instrument cluster, and replace the fuse.

Is the action complete? -

Verify repair

17 Replace the EPROM or ECM. Note) Refer to 6E1-243. - Verify repair -

Check the MIL driver circuit for a poor connection at the

instrument panel connector.

Was a problem found? -

Verify repair

Go to

Instrument

Panel in

Electrical

Diagnosis

DIAG NOSTI C TROUBLE CODE (DTC) 57 (FLASH DTC = 57)

CHECK ENGINE LAMP HI GH ERROR

HOT AT ALL TIMES

ECM

Fuse

15A

U/H

FUSE

BLOCK

HOT IN START AND RUN

Meter

Fuse

15A

I/P

FUSE

BLOCK

Malfuntion

Indicator

Lamp

0.85

YEL

1.25

RED/

WHT

1.25

RED/

WHT

0.5

BR/Y

Instrument

Panel(I/P)

Cluster

Engine

Control

Module

(ECM)

A4 A5 B4

Batt+ Malfunction

Indicator

Lamp

Control

TACHO

CIRCUIT DESCRIPTION

The malfunction indicator lamp (MIL) should always be

illuminated and steady with the ignition ON and the

engine stopped. Battery feed voltage is supplied

directly to the MIL indicator. The engine control

module (ECM) turns the MIL ON by grounding the MIL

driver circuit.

CONDITIO NS FOR SETTING THE DTC

•This code detects a low im pedance short to battery

on the MIL output.

•Driver f eedback infor m ation shows a low state at its

operation even when commanded high.

ACTIO N TAKEN WHEN THE DTC SETS

•The MIL will stay ON.

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection,

rubbed-through wire insulation, or a wire broken inside

the insulation. Check for the following items:

•Poor connection or damaged harness - Inspect the

ECM harness and connectors for improper mating,

broken locks, improperly formed or damaged

terminals, poor terminal-to-wire connection, and

damaged harness.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. If the MIL does not remain ON when the ECM is

disconnected, the MIL driver wiring is not faulty.

3. If the MIL driver circuit is OK, the instrum ent panel

cluster is faulty.

DTC (FLASH DTC = 57) CHECK ENGINE LAMP HIGH ERROR

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

21. Ignition OFF, disconnect ECM.

2. Ignition ON, observe the MIL.

Is the MIL ON? -

Go to Step 3 Go to Step 5

1. Ignition OFF, disconnect the instrument panel cluster.

2. Check the MIL driver circuit between the ECM and the

instrument panel cluster for a short to battery.

3. If a problem is found, repair as necessary.

Was the MIL driver circuit shorted to battery?

-Go to OBD

System Check

Go to Step 4

4Replace the instrument panel cluster.

Is the action complete? - Go to OBD

System Check -

1. Ignition OFF, reconnect the ECM.

2. Refer to On-Vehicle Service in Engine Control Module and

Sensors for procedures.

3. Using the scan tool output controls function, select MIL dash

lamp control and command the MIL OFF.

Did the MIL turn OFF?

-Go to OBD

System Check

Go to Step 6

6Replace the EPROM or ECM. Note) Refer to 6E1-243. -Go to OBD

System Check -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 61)

EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEMCANISTER

PURGE CONTROL VALVE CIRCUIT LOW ERROR (IF APPLICABLE)

Purge Control

0.5 R/L

CIRCUIT DESCRIPTION

The engine control Module (ECM) controls the

Evaporative Emission (EVAP) Canister Purge control

Solenoid Valve through the use of a control (ground)

circuit. If the ECM commands the Purge solenoid to

maximum duty cycle (100%) but the voltage remains

High (12 volts); or, if the ECM commands the Purge

solenoid to high duty cycle (100%) but the voltage

remains low (0 volts), this malfunction detects a low

impedance short to ground or open contact on the

canister purge solenoid output. Then DTC 61 will set.

CONDITIO NS FOR SETTING THE DTC

•Driver f eedback infor m ation shows a low state at its

operation even when commanded high.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the Malfunction Indicator

Lamp (MIL).

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•Poor connections, or a damaged harness - Inspect

the harness connectors for: backed-out terminals,

improper mating or dam aged terminals. Also check

for open circuits, shorts to ground, and shorts to

voltage.

•This malfunction detects a low impedance short to

ground or open contact on the purge control

solenoid output.

DTC (FLASH DTC = 61) EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM CANISTER

PURGE CONTROL VALVE CIRCUIT LOW ERROR

STEP ACTION VALUE(

S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? - Go to Step 2

Go to OBD

System Check

1. Ignition ON, Engine OFF.

2. Using the Scan Tool, monitor info for Diagnostic Trouble

Code 61.

Does the Scan Tool indicate DTC 61.

-Refer to

Diagnostic Aids Go to Step 3

1. Ignition OFF.

2. Disconnect the EVAP Canister Purge Control Solenoid from

the wiring harness connector from the EVAP Canister Purge

Control Solenoid.

3. Ignition ON, Engine OFF.

4. Using a Digital Voltmeter (DVM), check for voltage on the

"Engine IG." Fuse pin of the EVAP Canister Purge Control

Solenoid wiring harness connector.

Does the DVM read the following value? 12 Volts Go to Step 5 Go to Step 4

Check the suspect circuit between the EVAP Canister Purge

Control Solenoid connector and the "Engine IG." Fuse for the

following conditions:

•A short to ground

•An open circuit

•A short to voltage

Was the problem found?

Verify repair -

5Using a DVM, check the resistance of the EVAP Canister Purge

Control Solenoid.

Does the DVM read the following value?

less than

5 ohms

Go to Step 6 Go to Step 7

6Replace the EVAP Canister Purge Control Solenoid.

Verify repair. ---

7 Replace the EPROM or ECM. Note) Refer to 6E1-243. - - -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 62)

EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM CANISTER

PURGE CONTROL VALVE CIRCUIT HIGH ERROR (IF APPLICABLE)

Purge Control

0.5 R/L

CIRCUIT DESCRIPTION

The engine control Module (ECM) controls the

Evaporative Emission (EVAP) Canister Purge

Solenoid Valve through the use of a control (ground)

circuit. If the ECM commands the Purge solenoid to

maximum duty cycle (100%) but the voltage remains

High (12 volts); or, if the ECM commands the Purge

solenoid to minimum duty cycle (0%) but the voltage

remains high (12 volts), this malfunction detects a high

impedance short to ground or open contact on the

canister purge solenoid output. Then DTC 62 will set.

CONDITIO NS FOR SETTING THE DTC

•Driver feedback information shows a high state at

its operation even when commanded low.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the Malfunction Indicator

Lamp (MIL).

CONDITIO NS FOR CLEARI NG THE MIL/DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•Poor connections, or a damaged harness - Inspect

the harness connectors for: backed-out terminals,

improper mating or dam aged terminals. Also check

for open circuits, shorts to ground, and shorts to

voltage.

•This malf unction detects a high impedance short to

ground or open contact on the purge control

solenoid output.

DTC (FLASH DTC = 62) EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM CANISTER

PURGE CONTROL VALVE CIRCUIT HIGH ERROR

STEP ACTION VALUE(

S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? - Go to Step 2

Go to OBD

System Check

1. Ignition ON, Engine OFF.

2. Using the Scan Tool, monitor info for Diagnostic Trouble

Code 62.

Does the Scan Tool indicate DTC 62.

-Refer to

Diagnostic Aids Go to Step 3

1. Ignition OFF.

2. Disconnect the EVAP Canister Purge Control Solenoid from

the wiring harness connector from the EVAP Canister Purge

Control Solenoid.

Using a DVM, check the resistance of the EVAP Canister Purge

Control Solenoid.

Does the DVM read the following value?

less than

5 ohms

Go to Step 4 Go to Step 5

1. Ignition OFF.

2. Disconnect the engine Control Module (ECM) connectors

from the ECM.

3. Check the EVAP Canister Purge Control Solenoid control

circuit between the ECM and EVAP Canister Purge Control

Solenoid for the following conditions:

•A short to ground

•An open circuit

•A short to voltage

Was the problem found?

Verify repair Go to Step 6

5Replace the EVAP Canister Purge Control Solenoid.

Verify repair. ---

6 Replace the EPROM or ECM. Note) Refer to 6E1-243. - - -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 87)

A/C COMPRESSOR CLUTCH RELAY LOW ERROR

A/C

Compressor

Relay

Control

A16

MAG

Clutch

(Compressor)

Relay

Thermo

(1) (2)

(3) (4)

Relay:A/C

Compressor

Joint

To HA09

0.5

GR/R

B10

0.5

G/B

HOT IN START AND RUN

(2) (1)

(4) (3)

Engine

Control

Module

(ECM)

CIRCUIT DESCRIPTION

The engine control module (ECM) controls the A/C

Compressor Clutch Solenoid through the use of a

relay and a control (ground) circuit. This malfunction

detects a low impedance short to ground or open

contact on the A/C clutch relay output, then DTC 87

will set.

CONDITIO NS FOR SETTING THE DTC

•Driver f eedback infor m ation shows a low state at its

operation even when commanded high.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate Malfunction Indicator lamp

(MIL).

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•This malfunction detects a low impedance short to

ground or open contact on the AC clutch relay

output.

To diagnose an intermittent fault, check for the

following conditions:

•Poor connection at the ECM-Inspect harness

connections for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness-Inspect the wiring harness for

damage; shorts to Ground, shorts to Battery

Voltage, and Open circuits. If the harness appears

to be OK, observe the A/C clutch while moving

connectors and wiring harnesses related to the A/C.

A sudden clutch malfunction will indicate the source

of the intermittent fault.

A/C CLUTCH DIAGNOSIS

This chart should be used for diagnosing the electrical

portion of the A/C compressor clutch circuit. A Scan

Tool will be used in diagnosing the system. The Scan

Tool has the ability to read the A/C request input to the

ECM. The Scan Tool can display when the ECM has

commanded the A/C clutch ON. The Scan Tool should

have the ability to override the A/C request signal and

energize the A/C compressor relay.

DTC (FLASH DTC = 87) A/C COMPRESSOR CLUTCH RELAY LOW ERROR

STEP ACTION VALUE(

S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -Go to Step 2

Go to OBD

System Check

21. Ignition ON, engine OFF.

2. Using the Scan Tool, monitor info for DTC 87.

Does the Scan Tool indicate DTC 87?

-Refer to

Diagnostic Aids Go to Step 3

1. Ignition OFF.

2. Check for an open circuit at the pressure switch and thermo

switch.

And also check for an open circuit at the wire harness

between pressure switch and the ECM, pressure switch and

thermo switch, thermo switch and the Fuse.

Repair it necessary.

Verify Repair Go to Step 4

1. Remove the A/C Compressor Clu tch Relay from the

Underhood Electrical Center.

2. Ignition ON, engine OFF.

3. Using a Digital Voltmeter (DVM), check for voltage on the

Fused pins of the A/C Compressor Clutch Relay connector.

Does the DVM read the following value?

12 Volts

Go to Step 6 Go to Step 5

Check the suspect circuit(s) between the A/C Compressor

Clutch Relay connector and the Fuse for the following

conditions:

•A short to ground

•An open circuit

Was the problem found?

Verify Repair

STEP ACTION VALUE(

S) YES NO

1. Ignition OFF.

2. Disconnect the Engine Control Module (ECM) connectors

from the ECM.

3. Check the A/C Compressor Clutch Relay control circuit

between the ECM and Underhood Electrical Center for the

following conditions:

•A short to ground

•An open circuit

Was the problem found?

Verify Repair Go to Step 7

1. Reinstall the A/C Compressor Clutch Relay.

2. Using a fused jumper, ground the A/C Compressor Clutch

Relay control circuit at the ECM connector.

3. Ignition ON, Engine OFF.

Does the A/C Compressor turn ON?

Go to Step 10 Go to Step 8

1. Ignition OFF.

2. Check the A/C Compressor Clutch circuit between the A/C

Compressor Clutch Relay and A/C Compressor Clutch for

the following conditions:

•A short to ground

•An open circuit

Was the problem found?

Verify Repair Go to Step 9

9Replace the A/C Compressor Clutch Relay.

Is the action complete? -Verify Repair -

10 Replace the EPROM or ECM.

Varify Repair Note) Refer to 6E1-243. -- -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 88)

A/C COMPRESSOR CLUTCH RELAY HIGH ERROR

Engine

Control

Module

(ECM)

A/C

Compressor

Relay

Control

A16 B10

Thermo

Switch

Pressure

Switch

0.5G/W 0.5G/W

0.5G/W

A/C Switch

0.5

G/Y

0.5

GR/Y

0.5

G/R

0.5

G/B

CIRCUIT DESCRIPTION

The engine control module (ECM) controls the A/C

Compressor Clutch Solenoid through the use of a

relay and a control (ground) circuit. This malfunction

detects a low impedance short to ground or open

contact on the A/C clutch relay output, then DTC 88

will set.

CONDITIO NS FOR SETTING THE DTC

•Driver feedback information shows a high state at

its operation even when commanded low.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate Malfunction Indicator lamp

(MIL).

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•This malfunction detects a low impedance short to

battery on the AC clutch relay output.

To diagnose an intermittent fault, check for the

following conditions:

•Poor connection at the ECM-Inspect harness

connections for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness-Inspect the wiring harness for

damage; shorts to Battery Voltage, and Open

circuits. If the harness appears to be OK, observe

the A/C clutch while moving connectors and wiring

harnesses related to the A/C. A sudden clutch

malfunction will indicate the source of the

intermittent fault.

A/C CLUTCH DIAGNOSIS

This chart should be used for diagnosing the electrical

portion of the A/C compressor clutch circuit. A Scan

Tool will be used in diagnosing the system. The Scan

Tool has the ability to read the A/C request input to the

ECM. The Scan Tool can display when the ECM has

commanded the A/C clutch ON. The Scan Tool should

have the ability to override the A/C request signal and

energize the A/C compressor relay.

DTC (FLASH DTC = 88) A/C COMPRESSOR CLUTCH RELAY HIGH ERROR

STE

PACTION VALUE

(S)YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -Go to Step 2 Go to OBD

System Check

21. Ignition ON, engine OFF.

2. Using the Scan Tool, monitor info for DTC 88.

Does the Scan Tool indicate DTC 88? -Refer to

Diagnostic Aids Go to Step 3

1. Ignition OFF.

2. Remove the A/C Compressor Clutch Relay from the

Underhood Electrical Center.

3. Ignition ON, engine OFF.

4. Using a Digital Voltmeter (DVM), check for voltage on

the Fused pins of the A/C Compressor Clutch Relay

connector.

Does the DVM read the following value?

12 Volts

Go to Step 4 Go to Step 5

1. Ignition OFF.

2. Disconnect the Engine Control Module (ECM)

connectors from the ECM.

3. Check the A/C Compressor Clutch Relay control circuit

between the ECM and Underhood Electrical Center for

the following conditions:

•A short to battery

Was the problem found?

Verify Repair Go to Step 5

1. Reinstall the A/C Compressor Clutch Relay.

2. Using a fused jumper, ground the A/C Compressor

Clutch Relay control circuit at the ECM connector.

3. Ignition ON, Engine OFF.

Does the A/C Compressor turn ON?

Go to Step 8 Go to Step 6

1. Ignition OFF.

2. Check the A/C Compressor Clutch circuit between the

A/C Compressor Clutch Relay and A/C Compressor

Clutch for the following conditions:

•A short to battery

Was the problem found?

Verify Repair Go to Step 7

7Replace the A/C Compressor Clutch Relay.

Is the action complete? -Verify Repair -

8Replace the EPROM or ECM.

Varify Repair Note) Refer to 6E1-243. -- -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 93)

QUAD DRIVER SUB MODULE

CIRCUIT DESCRIPTION

Quad Driver Sub Module (QDSM) are used by the

engine control module (ECM) to turn ON many of the

current-driven devices that are needed to control

various engine and transmission functions. Each

QDSM is capable of controlling up to 4 separate

outputs by applying ground to the device which the

ECM is commanding ON.

QDSMs have the capability of diagnosing each output

circuit individually. DTC 93 set indicates an improper

voltage level has been detected on a QDSM output.

This DTC detects a short to battery or Open Load or

Short to ground at the QDSM output, then DTC P93

will set.

CONDITIO NS FOR SETTING THE DTC

•If fault line from the QDSM is detected low.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL).

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper

mating, broken locks, improperly formed or

damaged terminals, and poor terminal-to-wire

connection.

• Damaged harness - Inspect the wiring harness for

damage. If the harness appears to be OK,

disconnect the ECM, turn the ignition ON and

observe a voltmeter connected to the MIL driver

circuit at the ECM harness connector while moving

connectors and rewiring harnesses relates to the

MIL. A change in voltage will indicate the location of

the fault.

This malfunction detects a:

Short to battery or Open Load or Short to ground at

QDSM output.

DTC (FLASH DTC = 93) QUAD DRIVER SUB MODULE

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

2Replace the EPROM or ECM. Note) Refer to 6E1-243.

Is the action complete? -Verify Repair -

DIAG NOSTIC TROUBLE CODE DTC (FLASH DTC=51)

ELECTRICALLY PROGRAMMABLE READ-ONLY MEMORY (EPROM) ERROR

CIRCUIT DESCRIPTION

The Engine control module (ECM) used in this vehicle

utilizes an electrically programmable read- only

memory (EPROM). The EPROM contains program ID-

Calibration variable.

This malfunction checks the integrity of the EPROM

(ECM will not run), then DTC 51 will set.

CONDITIO NS FOR SETTING THE DTC

•If calculated check sum is not equal to the stored

check sum.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the malfunction is detected.

CONDITIONS FOR CLEARING THE MIL/DTC

• Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery

for more than 30 seconds.

2. A service tool such as Tech 2 is used to clear

them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

• Diagnostic Trouble Code 51 indicates that the ECM

will not run. The only possible repair is the EPROM

or ECM replacement.

DTC (FLASH DTC = 51) ELECTRICALLY PROGRAMMABLE READ-ONLY MEMORY (EPROM)

ERROR

ACTION VALUE(S) YES NO

Was the "On-Board Diagnostic (OBD) System Check" performed? -

Go to step 2

Go to OBD

System Check

Refer to Service Bulletins.

Is there still a problem? -Go to step 3 Verify Repair

Replace the EPROM or ECM.

Is the action complerte? Note) Refer to 6E1-243. Verify Repair -

DIAG NOSTIC TROUBLE CODE DTC (FLASH DTC = 55) ELECTRICALLY

ERASABLE PROGRAMMABLE READ-ONLY MEM O RY (EEPROM) ERROR

CIRCUIT DESCRIPTION

The Engine control module (ECM) used in this vehicle

utilizes an electrically erasable programmable read-

only memory (EEPROM). The EEPROM contains

program information and the calibrations required for

engine, diagnostics operation.

This malfunction checks the integrity of

microprocessor config resister located in the

EEPROM (ECM will not run), then DTC 55 will set.

CONDITIO NS FOR SETTING THE DTC

•The ECM detects an internal program fault.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will illuminate the malfunction indicator

lamp (MIL) the first time the malfunction is detected.

CONDITIONS FOR CLEARING THE MIL/DTC

• Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery

for more than 30 seconds.

2. A service tool such as Tech 2 is used to clear

them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

• Diagnostic Trouble Code 55 indicates that ECM will

not run. The only possible repair is the EPROM or

ECM replacement.

DTC (FLASH DTC = 55) ELECTRICALLY ERASABLE

PROGRAMMABLE READ-ONLY MEMORY ERROR

ACTION VALUE(S) YES NO

Was the "On-Board Diagnostic (OBD) System Check" performed? -

Go to step 2

Go to OBD

System Check

Refer to Service Bulletins.

Is there still a problem? -Go to step 3 Verify Repair

Replace the EPROM or ECM.

Is the action complerte? Note) Refer to 6E1-243. Verify Repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 91)

TACHO OUT LOW ERROR

0.5

B/R

0.5

Engine

Control

Module

(ECM)

Crank

Angle

Sensor

E5 B5

Tacho

Meter

Fuse

15A

CIRCUIT DESCRIPTION

Based on the information from the Crank Position

Sensor (CKP), X58 reference signal is generated at

each rotation of the crankshaft.

Engine Control Module (ECM) converts X58 reference

signal into rectangle wave and delivers it as output

signal to drive the pulse motor of the crankshaft.

When the wave length of the output signal is long, the

tacho meter indicates the engine speed is low, and

vise versa.

This malfunction detects a low impedance short to

ground or open contact on the Tacho output, the

Diagnostic Trouble Code 91 will be set.

CONDITIO NS FOR SETTING THE DTC

•Driver f eedback infor m ation shows a low state at its

operation even when commanded low.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will turn ON the Malfunction Indicator

Lamp

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•Poor connections or a damaged harness - Inspect

the harness connections for: backed out terminals,

imprope, mating or damaged terminals. Also check

for open circuit, short to ground, and short to

voltage.

•This malfunction detects a low impedance short to

ground or open contact on the ECM out put circuit.

DTC (FLASH DTC = 91) TACHO OUT LOW ERROR

STEP ACTION VALUE(

S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -Go to Step 2

Go to OBD

System Check

1. Ignition OFF.

2. Check for a faulty connection or damaged terminals at the

ECM connector.

Was a problem found?

Verify repair Go to Step 3

3Check for a faulty connection or damaged terminals at the ECM

connector.

Was a problem found? -

Verify repair Go to Step 4

1. Check for an open or short to ground in the circuit between

the meter cluster connector and the ECM connector.

If a problem is found, repair as necessary. -

Verify repair Go to Step 5

51. Check for an open circuit between the meter cluster

connector and the ground.

If a problem is found, repair as necessary. -

Verify repair Go to Step 6

61. Check for an open circuit between the meter cluster and

battery feed.

If a problem is found, repair as necessary. -

Verify repair Go to Step 7

71. Disconnect the meter cluster Panel.

2. Check the tacho meter circuit for an open.

Was a problem found? -

Go to Step 5 Go to Step 9

1. Disconnect the ECM and CKP sensor.

2. Check for an open in the 58X reference circuit between the

connector and the ECM harness connector.

3. If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 9

1. Reconnect the ECM and CKP sensor.

2. Connect a Digital Voltmeter (DVM) to measure voltage on

the 58X reference circuit at the ECM connector.

3. Observe the voltage while cranking the engine.

Is the voltage near the specified value?

2.5V

Go to Step 12 Go to Step 10

10 Check the connections at the CKP sensor and replace the

terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 11

11 Replace the CKP sensor.

Is the action complete? -Verify repair -

12 Check connections at the ECM and replace the terminals if

necessary.

Did any terminals require replacement? -

Verify repair Go to Step 13

13 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC =92)

TACHO OUT HIGH ERROR

0.5

B/R

0.5

Engine

Control

Module

(ECM)

Crank

Angle

Sensor

E5 B5

Tacho

Meter

Fuse

15A

CIRCUIT DESCRIPTION

Based on the information from the Crank Position

Sensor (CKP), X58 reference signal is generated at

each rotation of the crankshaft.

Engine Control Module (ECM) converts X58 reference

signal into rectangler wave and delivers it as output

signal to drive the pulse motor of the crankshaft.

When the wave length of the output signal is long, the

tacho meter indicates the engine speed is low, and

vise versa.

This malfunction detects a low impedance short to

battery or on the Tacho output, then Diagnostic

Trouble Code 92 will be set.

CONDITIO NS FOR SETTING THE DTC

•Driver f eedback infor m ation shows a low state at its

operation even when commanded low.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will turn ON the Malfunction Indicator

Lamp

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

•Poor connections or a damaged harness - Inspect

the harness connections for: backed out terminals,

imprope, mating or damaged terminals. Also check

for open circuit, and short to battery.

DTC (FLASH DTC = 92) TACHO OUT HIGH ERROR

STEP ACTION VALUE(S) YES NO

1Was the "On-Board Diagnostic (OBD) System Check"

performed? -

Go to Step 2

Go to OBD

System Check

1. Ignition OFF.

2. Check for a faulty connection or damaged terminals at the

tacho meter connector.

Was a problem found?

Verify repair Go to Step 3

3Check for a faulty connection or damaged terminals at the ECM

connector.

Was a problem found? -

Verify repair Go to Step 4

Check for a short circuit between the meter cluster connector

and the ECM.

If a problem is found, repair the wire harness.

Is there still a problem?

Verify repair Go to Step 5

51. Disconnect the ECM.

2. Check the ignition control circuit for a short to voltage.

Was a problem found? -

Verify repair Go to Step 6

6Replace the meter cluster.

Verify repair.

Is there still a problem? -

Go to Step 8

Refer to CKP

Sensor Signal

Incorrect

1. Disconnect the ECM and CKP sensor.

2. Check for a short to ground in the 58X reference circuit

between the CKP sensor connector and the ECM harness

connector.

3. If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 8

1. Reconnect the ECM and CKP sensor.

2. Connect a Digital Voltmeter (DVM) to measure voltage on

the 58X reference circuit at the ECM connector.

3. Observe the voltage while cranking the engine.

Is the voltage near the specified value?

2.5V

Go to Step 11 Go to Step 9

9Check the connections at the CKP sensor and replace the

terminals if necessary.

Did any terminals require replacement? -

Verify repair Go to Step 10

10 Replace the CKP sensor.

Is the action complete? -Verify repair -

11 Check connections at the ECM and replace the terminals if

necessary.

Did any terminals require replacement? -

Verify repair Go to Step 12

12 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 29)

FUEL PUMP RELAY SHORTED TO GROUND

Fuel

Pump

Fuse

20A

Relay

Fuel

Pump

A13

Fuel

Injectors

Fuel

Pump M

0.85W

Battery Joint Cable

0.5

G/W

Engine

Control

Module

(ECM)

ECM

Fuse

15A

CIRCUIT DESCRIPTION

When the ignition switch is first turned ON, the engine

control module (ECM) energizes the fuel pump relay

which applies power to the in-tank fuel pump. The fuel

pump relay will remain ON as long as the engine is

running or cranking and the ECM is receiving 58X

crankshaft position pulses. If no 58X crankshaft

position pulses are present, the ECM de-energizes the

fuel pump relay within 2 seconds after the ignition is

turned ON or the engine is stopped.

The fuel pump delivers fuel to the fuel rail and

injectors, then to the fuel pressure regulator. The fuel

pressure regulator controls fuel pressure by allowing

excess fuel to be returned to the fuel tank. With the

engine stopped and ignition ON, the fuel pump can be

turned ON by using a command by the scan tool.

This code detects a fuel pump relay short to ground or

disconnected.

CONDITIO NS FOR SETTING THE DTC

•ECM has commanded Fuel Pump relay to be de-

energized.

•Feedback information shows relay is still energized

or, an open contact is present.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will turn ON the Malfunction Indicator

Lamp.

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection,

rubbed-through wire insulation, or a wire broken inside

the insulation. Check for the following items:

• Poor connection or damaged harness - Inspect the

ECM harness and connectors for improper mating,

broken locks, improperly formed or damaged

terminals, poor terminal-to-wire connection, and

damaged harness.

• This malfunction detects a fuel pump relay short to

ground or disconnection.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. If the fuel pump is operating but incorrect pressure

is noted, the fuel pump wiring is OK and the “Fuel

System Pressure Test” chart should be used for

diagnosis.

CAUTION: To reduce the risk of fire and

personal injury:

• It is necessary to relieve fuel system

pressure before connecting a fuel pressure

gauge. Refer to Fuel Pressure Relief

Procedure, below.

• A small amount of fuel may be released

when disconnecting the fuel lines. Cover

fuel line fittings with a shop towel before

disconnecting, to catch any fuel that may

leak out. Place the towel in an approved

container when the disconnect is

completed.

FUEL PRESSURE RELIEF PROCEDURE

1. Remove the fuel cap.

2. Remove the fuel pump relay from the underhood

relay center.

3. Start the engine and alow it to stall.

4. Crank the engine for an additional 3 seconds.

FUEL PRESSURE GAUGE INSTALLATION

1. Remove the shoulder fitting cap.

2. Install fuel pressure gauge 5-8840-0378-0 to the

fuel feed line located in front of and above the right

side valve cover.

3. Reinstall the fuel pump relay.

DTC (FLASH DTC = 29) FUEL PUMP RELAY SHORTED TO GROUND

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

1. Read the “Caution” above.

2. Relieve the fuel system pressure and install the fuel pump

pressure gauge to the test fitting.

3. Use a scan tool to command the fuel pump ON.

Is there an immediate pressure build-up which indicates the

pump is running?

Go to Step 3 Go to Step 4

1. Verify that the pump is not running by removing the fuel filler

cap and listening.

2. Check the fuel pump relay connector is loosely fitting or

disconnected.

Repair it necessary.

3. Command the pump ON with the scan tool.

Did the pump turn OFF after 2 seconds?

Test

completed Go to Step 4

STEP ACTION VALUE(S) YES NO

1. Ignition OFF.

2. Remove the fuel pump relay.

3. Connect a test light between the two wires that connect to

the fuel pump relay pull-in coil.

4. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off?

Go to Step 9 Go to Step 5

1. With a test light connected to battery (−), probe the fuel

pump relay connector at the wire which runs form the relay

pull-in coil to the ECM.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off?

Go to Step 6 Go to Step 7

6Check for short to ground between the ECM and the fuel pump

relay.

Was a problem found?

Verify repair Go to Step 7

1. Check the fuel pump relay circuit for a poor terminal

connection at the ECM.

2. If a problem is found, replace terminal as necessary.

Was a problem found?

Verify repair Go to Step 8

8Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

1. Honk the horn to verify that the horn relay is functioning.

2. Substitute the horn relay for the fuel pump relay.

3. Leave the test light connected as in step 12.

4. Command the fuel pump ON with the scan tool.

Did the test light illuminate for 2 seconds when the fuel pump

was commanded ON?

Go to Step 13 Go to Step 10

1. Re-connect the horn relay in its proper location.

2. Check for a short circuit, blown fuse or open circuit between

the relay and the fuel tank.

Is the action complete?

Verify repair

1. With the fuel pump electrical connector at the fuel tank

disconnected, connect a test light between the feed wire and

the ground wire (harness side).

2. Command the fuel pump ON with a scan tool.

Did the test light illuminate for 2 seconds?

Go to Step 14 Go to Step 12

12 Repair the open circuit in the fuel pump ground wire.

Is the action complete? -Verify repair -

13 1. Re-connect the horn relay in its proper location.

2. Replace the fuel pump relay.

Is the action complete? -

Verify repair

14 Replace the fuel pump.

Is the action complete? -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC = 32)

FUEL PUMP RELAY SHORTED TO BATTERY

Fuel

Pump

Fuse

20A

Relay

Fuel

Pump

A13

Fuel

Injectors

Fuel

Pump M

0.85W

Battery Joint Cable

0.5

G/W

Engine

Control

Module

(ECM)

ECM

Fuse

15A

CIRCUIT DESCRIPTION

When the ignition switch is first turned ON, the engine

control module (ECM) energizes the fuel pump relay

which applies power to the in-tank fuel pump. The fuel

pump relay will remain ON as long as the engine is

running or cranking and the ECM is receiving 58X

crankshaft position pulses. If no 58X crankshaft

position pulses are present, the ECM de-energizes the

fuel pump relay within 2 seconds after the ignition is

turned ON or the engine is stopped.

The fuel pump delivers fuel to the fuel rail and

injectors, then to the fuel pressure regulator. The fuel

pressure regulator controls fuel pressure by allowing

excess fuel to be returned to the fuel tank. With the

engine stopped and ignition ON, the fuel pump can be

turned ON by using a command by the scan tool.

This code detects a fuel pump relay short to battery.

CONDITIO NS FOR SETTING THE DTC

•ECM has commanded Fuel Pump relay to be

energized.

•Feedback information shows relay is still de-

energized.

ACTIO N TAKEN WHEN THE DTC SETS

•The ECM will turn ON the Malfunction Indicator

Lamp.

CONDITIO NS FOR CLEARI NG THE DTC

Once the ECM determines that a fault(s) has been

rectified then the CEL will switch OFF, although the

fault code will remain in the ECM memory.

Any fault codes will remain in ECM memory until -

1. They are cleared by disconnecting the Battery for

more than 30 seconds.

2. A service tool such as Tech 2 is used to clear them.

3. Ten consecutive starts without logging a fault.

DIAGNOSTIC AIDS

An intermittent may be caused by a poor connection,

rubbed-through wire insulation, or a wire broken inside

the insulation. Check for the following items:

• Poor connection or damaged harness - Inspect the

ECM harness and connectors for improper mating,

broken locks, improperly formed or damaged

terminals, poor terminal-to-wire connection, and

damaged harness.

• Fuel pump relay short to battery.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the

Diagnostic Chart.

2. If the fuel pump is operating but incorrect pressure

is noted, the fuel pump wiring is OK and the “Fuel

System Pressure Test” chart should be used for

diagnosis.

CAUTION: To reduce the risk of fire and

personal injury:

• It is necessary to relieve fuel system

pressure before connecting a fuel pressure

gauge. Refer to Fuel Pressure Relief

Procedure, below.

• A small amount of fuel may be released

when disconnecting the fuel lines. Cover

fuel line fittings with a shop towel before

disconnecting, to catch any fuel that may

leak out. Place the towel in an approved

container when the disconnect is

completed.

FUEL PRESSURE RELIEF PROCEDURE

1. Remove the fuel cap.

2. Remove the fuel pump relay from the underhood

relay center.

3. Start the engine and alow it to stall.

4. Crank the engine for an additional 3 seconds.

FUEL PRESSURE GAUGE INSTALLATION

1. Remove the shoulder fitting cap.

2. Install fuel pressure gauge 5-8840-0378-0 to the

fuel feed line located in front of and above the right

side valve cover.

3. Reinstall the fuel pump relay.

DTC (FLASH DTC = 32) FUEL PUMP RELAY SHORTED TO BATTERY

STEP ACTION VALUE(S) YES NO

1Was the “On-Board Diagnostic (OBD) System

Check” performed? -

Go to Step 2

Go to OBD

System Check

1. Read the “Caution” above.

2. Relieve the fuel system pressure and install the fuel pump

pressure gauge to the test fitting.

3. Use a scan tool to command the fuel pump ON.

Is there an immediate pressure build-up which indicates the

pump is running?

Go to Step 3 Go to Step 4

1. Verify that the pump is not running by removing the fuel filler

cap and listening.

2. Command the pump ON with the scan tool.

Did the pump turn OFF after 2 seconds?

-Test

completed Go to Step 12

1. Ignition OFF.

2. Remove the fuel pump relay.

3. Using a test light connected to ground, probe the battery

feed to the relay.

Did the light illuminate?

Go to Step 6 Go to Step 5

5Repair short or open battery feed to fuel pump relay.

Is the action complete? -Verify repair -

STEP ACTION VALUE(S) YES NO

1. Connect a test light between the two wires that connect to

the fuel pump relay pull-in coil.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off? -

Go to Step 12 Go to Step 7

1. With a test light connected to battery (−), probe the fuel

pump relay connector at the wire which runs form the relay

pull-in coil to the ECM.

2. Ignition ON.

Did the test light illuminate for 2 seconds and then turn off?

Go to Step 8 Go to Step 9

8Locate and repair open in the fuel pump relay ground circuit. Is

the action complete? -Verify repair -

1. Check for short or open between the battery and the fuel

pump relay.

2. Check the fuel pump relay circuit for a poor terminal

connection at the ECM.

3. If a problem is found, replace terminal as necessary.

Was a problem found?

Verify repair Go to Step 10

10 Replace the EPROM or ECM.

Is the action complete? Note) Refer to 6E1-243. -Verify repair -

1. Reconnect the fuel pump relay.

2. Disconnect the fuel pump electrical connector at the fuel

tank

3. Using a test light connected to ground, probe the fuel pump

feed wire (harness side).

4. Command the fuel pump ON with a scan tool.

Did the light illuminate for 2 seconds?

Go to Step 14 Go to Step 12

1. Honk the horn to verify that the horn relay is functioning.

2. Substitute the horn relay for the fuel pump relay.

3. Leave the test light connected as in step 11.

4. Command the fuel pump ON with the scan tool.

Did the test light illuminate for 2 seconds when the fuel pump

was commanded ON?

Go to Step 16 Go to Step 13

STEP ACTION VALUE(S) YES NO

1. Re-connect the horn relay in its proper location.

2. Check for a short circuit, blown fuse or open circuit between

the relay and the fuel tank.

Is the action complete?

Verify repair

1. With the fuel pump electrical connector at the fuel tank

disconnected, connect a test light between the feed wire and

the ground wire (harness side).

2. Command the fuel pump ON with a scan tool.

Did the test light illuminate for 2 seconds?

Go to Step 17 Go to Step 15

15 Repair the open circuit in the fuel pump ground wire.

Is the action complete? -Verify repair -

16 1. Re-connect the horn relay in its proper location.

2. Replace the fuel pump relay.

Is the action complete? -

Verify repair

17 Replace the fuel pump.

Is the action complete? -Verify repair -

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC=83)

RECEIVED RESPONSE WAS NOT CORRECT

KEY

TRANSPONDER

ENCRYPT

TECH-2

CARTRIDGE

ENCRYPT

BATTERY

IGN''ON'' IGN''ON'' IGN''ON''

GND BATTERY

INJECTION:STOP

IGNITION:STOP

GND

CPU ECM

ANTENNA COIL

RELAY

(STARTER CUT)

VEHICLE

SPEED SENSOR

IMMOBILIZER

CONTROL UNIT

VSS IN

OTHER SYSTEM DIAGNOSIS

VEHICLE SPEED SENSOR LINE

VSS OUT

CHECK

ENGINE

LAMP

(MIL) ENGINE

MANAGEMENT

SYSTEM

DIAGNOSIS

DLC

CIRCUIT DESCRIPTION

An encrypted signal is transmitted from the

Immobiliser Control Unit to the ECM when the ignition

is turned ON.

CONDITION FOR SETTING THE DTC

A DTC 83 will set when:

• An incorrect signal is transmitted from the ICU to

the ECM within 0.5 secs of turning the ignition ON.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

CONDITIO N FOR CLEARI NG THE MIL/DTC

•Use clear DTC information with TECH 2 - Refer to

Section 0C TECH 2 Diagnosis

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM and Immobiliser-Inspect

harness connectors for backed out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, and poor terminal to wire

connection.

• Damaged harness-Inspect the wiring harness for

damage, If the harness appears to be OK,

disconnect the ECM and Immobiliser, turn the

ignition "ON" and obs erve a voltm eter c onnected to

the suspect driver circuit at the ECM and

Immobiliser harness connector while moving

connectors and wiring harnesses that relate to the

MIL. A change in voltage will indicate the location

of the fault.

DTC (FLASH DTC=83) RECEIVED RESPONSE WAS NOT CORRECT

STEP ACTION VALUE(S) YES NO

1 Was the "On-Board Diagnostic (OBD) system Check" performed? -Go to Step 2

Go to OBD

system

check

2 Check the ECM and ICU harness and connectors for:

1. Backed out terminals, improper mating, broken locks, improperly

formed or damaged terminals and poor terminal to wire

connection.

2. Damaged harness - inspect the wiring harness for damage.

If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 3

3 Replace the ECM.

IMPORTANT: The replacement ECM must be programmed. Refer to

Section OC-1 - Service programming.

IMPORTANT: Refer to Section 11A - Engine Immobiliser System for

the Immobiliser Programming Procedure

IMPORTANT: Ensure the latest software program is downloaded to the

ECM.

Is the action complete?

Verify repair

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC=84)

NO RESPONSE FROM IMM OBILISER

KEY

TRANSPONDER

ENCRYPT

TECH-2

CARTRIDGE

ENCRYPT

BATTERY

IGN''ON'' IGN''ON'' IGN''ON''

GND BATTERY

INJECTION:STOP

IGNITION:STOP

GND

CPU ECM

ANTENNA COIL

RELAY

(STARTER CUT)

VEHICLE

SPEED SENSOR

IMMOBILIZER

CONTROL UNIT

VSS IN

OTHER SYSTEM DIAGNOSIS

VEHICLE SPEED SENSOR LINE

VSS OUT

CHECK

ENGINE

LAMP

(MIL) ENGINE

MANAGEMENT

SYSTEM

DIAGNOSIS

DLC

CIRCUIT DESCRIPTION

An encrypted signal is transmitted from the

Immobiliser Control Unit to the ECM when the ignition

is turned ON.

CONDITION FOR SETTING THE DTC

A DTC 84 will set when:

• No signal is transmitted from the ICU to the ECM

within 0.5 secs of turning the ignition ON.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

CONDITIO N FOR CLEARI NG THE MIL/DTC

•Use clear DTC information with TECH 2 - Refer to

Section 0C TECH 2 Diagnosis

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM and Immobiliser-Inspect

harness connectors for backed out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, and poor terminal to wire

connection.

• Damaged harness-Inspect the wiring harness for

damage, If the harness appears to be OK,

disconnect the ECM and Immobiliser, turn the

ignition "ON" and obs erve a voltm eter c onnected to

the suspect driver circuit at the ECM and

Immobiliser harness connector while moving

connectors and wiring harnesses that relate to the

MIL. A change in voltage will indicate the location

of the fault.

DTC (FLASH DTC=84) NO RESPONSE FROM IMMOBILISER

STEP ACTION VALUE(S) YES NO

1 Was the "On-Board Diagnostic (OBD) system Check" performed?

-Go to Step 2

Go to OBD

system

check

2 Using the Tech2 system selection menu, select Body function.

Does the Tec h2 indic ate DTC B****?

Refer to

Section 11A -

Engine

Immobiliser

System

Go to Step 3

3 Does the Tech2 indicate DTC 84? -Go to Step 4

Refer to

Diagnostic

Aids

4 Check the ECM and ICU harness and connectors for:

1. Backed out terminals, improper mating, broken locks, improperly

formed or damaged terminals and poor terminal to wire

connection.

2. Damaged harness - inspect the wiring harness for damage.

If a problem is found, repair as necessary.

Was a problem found?

Verify repair Go to Step 5

5 1. Disconnect the Vehicle Speed Sensor line VSS OUT harness.

2. Check for an open circuit or short to ground in the wire between

the ECM pin 8 and ICU pin J1-E7 by DMM.

If a problem found, repair as necessary.

Was a problem found? - Verify repair Go to Step 6

6 Replace the ECM.

IMPORTANT: The replacement ECM must be programmed. Refer to

Section OC-1 - Service programming.

IMPORTANT: Refer to Section 11A - Engine Immobiliser System for

the Immobiliser Programming Procedure

IMPORTANT: Ensure the latest software program is downloaded to the

ECM.

Is the action complete?

Verify repair

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC=85)

SECURITY CODE & SECURITY KEY NOT PROGRAMME D

KEY

TRANSPONDER

ENCRYPT

TECH-2

CARTRIDGE

ENCRYPT

BATTERY

IGN''ON'' IGN''ON'' IGN''ON''

GND BATTERY

INJECTION:STOP

IGNITION:STOP

GND

CPU ECM

ANTENNA COIL

RELAY

(STARTER CUT)

VEHICLE

SPEED SENSOR

IMMOBILIZER

CONTROL UNIT

VSS IN

OTHER SYSTEM DIAGNOSIS

VEHICLE SPEED SENSOR LINE

VSS OUT

CHECK

ENGINE

LAMP

(MIL) ENGINE

MANAGEMENT

SYSTEM

DIAGNOSIS

DLC

CIRCUIT DESCRIPTION

The ECM is programmed with security information

during installation.

CONDITION FOR SETTING THE DTC

A DTC 85 will set when:

• The security c ode and the trans ponder k ey are not

programmed into the ECM.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

CONDITIO N FOR CLEARI NG THE MIL/DTC

•Use clear DTC information with TECH 2 - Refer to

Section 0C TECH 2 Diagnosis

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM and Immobiliser-Inspect

harness connectors for backed out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, and poor terminal to wire

connection.

• Damaged harness-Inspect the wiring harness for

damage, If the harness appears to be OK,

disconnect the ECM and Immobiliser, turn the

ignition "ON" and obs erve a voltm eter c onnected to

the suspect driver circuit at the ECM and

Immobiliser harness connector while moving

connectors and wiring harnesses that relate to the

MIL. A change in voltage will indicate the location

of the fault.

DTC (FLASH DTC=85) SECURITY CODE & SECRET KEY NOT PROGRAMMED

STEP ACTION VALUE(S) YES NO

1 Was the "On-Board Diagnostic (OBD) system Check"

performed? -Go to Step 2

Go to OBD

system

check

2 Using the Tech2 system selection menu, select Body function.

Does the Tec h2 indic ate DTC B****?

Refer to

Section 11A -

Engine

Immobiliser

System

Go to Step 3

3 Replace the ECM.

IMPORTANT: The replacement ECM must be programmed.

Refer to Section OC-1 - Service programming.

IMPORTANT: Refer to Section 11A - Engine Immobiliser

System for the Immobiliser Programming Procedure

IMPORTANT: Ensure the latest software program is

downloaded to the ECM.

Is the action complete?

Verify repair

DIAG NOSTI C TROUBLE CODE (DTC) (FLASH DTC=86)

RECEIVED INCORRECT SECURI TY CODE

KEY

TRANSPONDER

ENCRYPT

TECH-2

CARTRIDGE

ENCRYPT

BATTERY

IGN''ON'' IGN''ON'' IGN''ON''

GND BATTERY

INJECTION:STOP

IGNITION:STOP

GND

CPU ECM

ANTENNA COIL

RELAY

(STARTER CUT)

VEHICLE

SPEED SENSOR

IMMOBILIZER

CONTROL UNIT

VSS IN

OTHER SYSTEM DIAGNOSIS

VEHICLE SPEED SENSOR LINE

VSS OUT

CHECK

ENGINE

LAMP

(MIL) ENGINE

MANAGEMENT

SYSTEM

DIAGNOSIS

DLC

CIRCUIT DESCRIPTION

The ICU transmits a security code to the ECM when

the ignition is turned ON.

CONDITION FOR SETTING THE DTC

A DTC 86 will set when:

• An incorrect signal is transmitted from the ICU to

the ECM.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

ACTIO N TAKEN WHEN THE DTC SETS

• Rapid (4Hz) flashing of the MIL ("CHECK

ENGINE" lamp).

• The engine does not start.

CONDITIO N FOR CLEARI NG THE MIL/DTC

•Use clear DTC information with TECH 2 - Refer to

Section 0C TECH 2 Diagnosis

DIAGNOSTIC AIDS

Check for the following conditions:

• Poor connection at ECM and Immobiliser-Inspect

harness connectors for backed out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, and poor terminal to wire

connection.

• Damaged harness-Inspect the wiring harness for

damage, If the harness appears to be OK,

disconnect the ECM and Immobiliser, turn the

ignition "ON" and obs erve a voltm eter c onnected to

the suspect driver circuit at the ECM and

Immobiliser harness connector while moving

connectors and wiring harnesses that relate to the

MIL. A change in voltage will indicate the location

of the fault.

DTC (FLASH DTC=86) RECEIVED INCORRECT SECURITY CODE

STEP ACTION VALUE(S) YES NO

1 Was the "On-Board Diagnostic (OBD) system Check"

performed? -Go to Step 2

Go to OBD

system

check

2 Recheck the security code.

Is the action complete? - Verify repair -

ON-VEHICLE SERVICE PROCEDURE ECM AND SENSORS

CRANKSHAFT POSITION ( CKP) SENSOR

REMOVAL

1. Disconnect the negative battery cable.

2. Remove the drive belt. Refer to

Engine Mechanical Section.

3. Remove the A/C compressor from engine. Refer to

A/C compressor

4. Disconnect electrical connector from the sensor.

5. Remove the retaining bolt and sensor from the engine

block.

Note: Use caution to avoid any hot oil that might drip out.

INSTALLATION

1. Install the crank shaft position sensor to its position.

2. Install and tighten the mounting bolt. Refer to

Engine Mechanical Section.

3. Reinstall the A/C compressor to the engine.

4. Reinstall the accessory drive belt.

5. Connect the negative battery cable.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

REMOVAL

1. Disconnect the negative battery cable.

2. Drain enough engine coolant so that the coolant level will

be below the ECT sensor.

3. Remove electrical connector from the sensor located on

the thermostat housing.

4. Unscrew the sensor from the thermostat housing.

INSTALLATION

1. Install the sensor into the thermostat housing. Do not

over tighten.

2. Connect electrical connector.

3. Add engine coolant to required level. Refer to

Engine Cooling Sys tem Section.

4. Connect the negative battery cable.

HEATED OXYG EN SENSO R (HO2S) (IF APPLI CABLE)

REMOVAL

1. Disconnect the negative battery cable.

2. The sensor is mounted on the exhaust pipe ahead of the

catalytic converter.

3. Disconnect pig tail electrical connector.

IMPORTANT: The pigtail is permanently attached to the

sensor. Be careful not to pull the wires out.

4. Unscrew sensor from the exhaust pipe. Because of the

expansion and contraction of the metal in the exhaust

system over time, this may be difficult if the engine

temperature is below 48 degree C.

INSPECTION

Note: The sensor is identical. Inspect each in the same way.

1. Inspect the pigtail and the electrical connector for grease,

dirt, corrosion and bare wire or worn insulation.

2. Inspect the louvered end of the sensor for grease, dirt,

excessive carbon build up or other contaminants.

INSTALLATION

Note: If HO2S is reinstalled after removal.

1. Install HO2S on the exhaust pipe.

2. Tighten the sensor to 55 Nm(7.6kgf⋅m).

3. Connect the pigtail to the wiring harness.

4. Connect the negative battery cable.

INTAKE AIR TEMPERATURE (IAT) SENSOR

REMOVAL

1. Disconnect the negative battery cable.

2. The IAT sensor is located in the intake air duct between

the air filter and the throttle body.

3. Disconnect the electrical connector from the sensor.

4. Remove the sensor from intake air duct by using a

rocking motion while pulling the sensor.

INSTALLATION

1. Install the IAT sensor into intake air duct. Make sure the

sensor is pushed all the way into the intake air duct.

2. Connect electrical connector.

3. Connect the negative battery cable.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSO R

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect the electrical connector from the sensor. (The

MAP sensor is located on the intake manifold behind

throttle body.)

3. Connect electrical connector.

4. Connect the negative battery cable.

INSTALLATION

1. Push MAP sensor into the manifold. Make sure the

sensor is pushed always into its position.

2. Install a mounting bolts and tighten.

3. Remove a mounting bolt securing the sensor to the

manifold.

4. Remove the sensor from the intake manifold using

rocking motion while pulling the sensor.

MALFUNCTION INDICATOR LAMP (M IL)

Refer to Instrument Panel Removal P rocedure.

ENGINE CONTROL MODULE (ECM )

ELECTROSTATIC DISCHARGE (ESD) DAMAGE

Electronic components used in the control system are often

designed to carry very low voltage. Electronic components are

susceptible to damage caused by electrostatic discharge. Less

than 100 volts of static electricity can cause damage to same

electronic components. By comparison, it takes as much as

4000 volts for a person to even feel the zap of a static

discharge. There are several way for a person to become

statically charged. The most common methods of charging are

by friction and by induction. An example of charging by friction

is a person sliding across a car seat. Charging by induction

occurs when a person with well insulated shoes stands near a

highly charged object and momentarily touches ground.

Charge of the same polarity are drained off leaving the person

highly charged with opposite polarity. Static charge can cause

damage, therefore, it is important to use care when handling

and testing electronic components.

Notice: To prevent possible Electrostatic Discharge damage,

follow these guidelines:

•Do not touch the control module connector pins or

soldered components on the control module circuit

board.

•Do not open the replacement part package until the part

is ready to be installed.

•Before removing the parts from the package, ground the

package to a known good ground on the vehicle.

•If the parts been handled while sliding across the seat, or

while sitting from standing position, or walking a distance,

touch a known good ground before installing the parts.

Notice: To prevent internal ECM damage, the ignition must be

OFF position in order to disconnect or reconnect power to the

ECM (for example: battery cable, pig-tail, ECM fuse, jumper

cable, etc.).

ENGINE CO NTROL MODULE (ECM)

REMOVAL

1. The ECM cover is located at the Instrument panel lower

center cover assembly.

2. Remove the center cover assembly.

3. Remove the three screws.

4. Pull out the ECM.

5. Disconnect both red and tan connectors.

6. Remove the four screws located on both sides and then

remove the brackets from the ECM.

INSTALLATION

1. Attach the brackets to both sides of the ECM main body

by securely tightening the screws.

2. Connect both red and tan connectors.

3. Replace the ECM to the original position by tightening the

screws.

4. Attach the center cover assembly.

POWER STEERING PRESSURE (PSP) SWI TCH

REMOVAL

1. Disconnect the battery negative cable.

2. Disconnect the PSP switch pigtail from the wiring

harness.

IMPORTANT: The pigtail is permanently attached to the

switch. Do not attempt to remove the wire from the switch.

IMPORTANT: Have container ready to catch the power

steering fluid that leaks out of the line when the switch is

removed.

3. Unscrew the PSP switch from the power steering pump.

INSTALLATION

1. Install the PSP switch into the power steering pump.

2. Connect electrical connector.

3. Ensure power steering fluid level and no leakage. Add

power steering fluid if necessary. Refer to

Power Steering Section.

4. Connect the negative battery cable.

THROTTLE POSITION SENSOR (TPS)

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect the TPS electrical connector.

3. Remove the two screws and TP sensor from the throttle

body.

Notice: Do not clean the TP sensor by soaking it in solvent.

The sensor will be damaged as a result.

FUNCTION CHECK

Use a Scan Tool to check the TP sensor output voltage at

closed throttle.

•The voltage should be under 0.25 volts.

•If the reading is greater than 0.25 volts, check the throttle

shaft to see if it is binding. Check that the throttle cable is

properly adjusted, also. Refer to

Throttle Cable Adjustme nt.

•If the throttle shaft is not binding and the throttle cable is

properly adjusted, install a new TP sensor.

INSTALLATION

1. Install the TP sensor on the throttle body with two

screws.

2. Connect the electrical connector.

3. Connect the negative battery cable.

VEHICLE SPEED SENSOR ( VSS)

REMOVAL

1. Disconnect the negative battery cable.

2. VSS is located on the right side of the transmission case

just ahead of the rear propeller shaft. Disconnect the

VSS electrical connector.

3. Remove the bolt and the VSS from the transmission

case by wiggling it slightly and pulling it straight out.

IMPORTANT: Have a container ready to catch any fluid that

leaks out when the VSS is removed from the transfer case.

INSPECTION

1. Inspect the electrical connector for signs of corrosion or

warping. Replace the VSS if the electrical connector is

corroded or warped.

2. Inspect the VSS driven gear for chips, breaks, or worn

condition. Replace the VSS if the driven gear is chipped,

broken or worn.

3. Inspect the O-ring for wear, nicks, tears, or looseness.

Replace the O-ring if necessary.

INSTALLATION

1. Install the VSS in the transmission case with the notch

for the connector facing the rear.

2. Secure the VSS with mounting bolt. Tighten the bolt to 16

N⋅m (17kgf⋅m).

3. Connect electrical connector to the VSS.

4. Check the transmission oil level. Add oil if necessary.

5. Connect the negative battery cable.

AIR INDUCTION SYSTEM

AIR FILTER

REMOVAL

1. Disconnect electrical connector at the IAT sensor.

2. Release the four latches securing the lid to the air

cleaner housing.

3. Remove the air cleaner lid.

4. Remove the air filter element.

INSTALLATION

1. Install the air filter element in the air cleaner housing.

2. Install the air cleaner lids.

3. Secure the three latches, holding the lid on the air

cleaner housing.

4. Connect the electrical connector to the IAT sensor.

IDLE AIR CONTROL (IAC) VALVE

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect the IAC electrical connector.

3. Remove the two screws and IAC valve from the throttle

body.

Notice: Do not clean the IAC valve by soaking it in solvent.

The valve will be damaged as a result.

CLEANI NG AND INSPECTION

•Clean the IAC valve O-ring sealing surface, pintle valve

seat and air passage.

•Use carburetor cleaner and a parts cleaning brush to

remove carbon deposit. Do not use a cleaner that contain

methyl ethyl ketone. This is an extremely strong solvent

and not necessary for this type of deposit.

•Shiny spots on the pintle are normal and do not indicate

misalignment or a bent pintle shaft.

•Inspect the IAC valve O-ring for cuts, cracks or distortion.

Replace the O-ring if damaged.

28mm

max.

MEASUREMENT

•In order to install a new IAC valve, measure the distance

between the tip of the pintle and the mounting flange. If

that measurement is 28 mm or less, the valve needs no

adjustment. If the measurement is greater than 28 mm,

apply finger pressure and retract the valve. The force

required to retract the pintle on a new valve will not

damage the valve, shaft or pintle.

Notice: Do not push or pull on the IAC valve pintle on IAC

valve that has been in service. The force required to move the

pintle may damage it.

Important: Use an identical replacement part in order to

replace a valve. IAC valve pintle shape and diameter are

designed for the specific application.

INSTALLATION

1. Install IAC valve on the throttle valve body with the two

screws. Tighten the screws to 1 N⋅m (1.2kgf⋅m).

2. Connect electrical connector to IAC valve.

3. Connect the negative battery cable.

INTAKE AIR DUCT

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect electrical connector at IAT sensor.

3. Remove the IAT sensor if necessary. Refer to

Intake Air Temperature Sensor Removal.

4. Loosen retaining clamps at the throttle body and at the

air filter box.

5. Disconnect brake booster vacuum hose at intake

manifold and at brake booster.

6. Remove retaining nut at the intake air duct bracket at top

of valve cover.

7. Disconnect the intake air duct from the throttle body and

at the air filter box.

INSTALLATION

1. Connect the intake air duct at the throttle body and at the

air filter box. Make sure retaining hole is inserted to the

intake air duct bracket.

2. Tighten retaining clamp at the throttle body and at the air

filter box.

3. Install a nut to the intake air duct bracket and tighten.

4. Connect brake booster vacuum hose to intake manifold

and to brake booster and secure them with clamps.

5. Install IAT sensor if necessary. Refer to

Intake Air Temperature Sensor Installation.

6. Connect electrical connector at IAT sensor.

7. Connect the negative battery cable.

Important: Use an identical replacement part in order to

replace a valve. IAC valve pintle shape and diameter are

designed for the specific application.

KNOCK SENSOR

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect pig tail electrical connector at near the top of

generator.

3. Unscrew retaining bolt from Knock Sensor located on the

passenger side of engine block just front of starter.

4. Remove Knock Sensor with retaining bolt.

INSTALLATION

1. Install Knock Sensor with retaining bolt. Tighten the

screws to 20N⋅m (2.0kgf⋅m).

2. Connect pigtail electrical connector.

3. Connect battery negative cable.

OIL PRESSURE SWITCH

REMOVAL

1. Disconnect battery negative cable.

2. Disconnect electrical connector at Oil Pressure Switch.

3. Unscrew Oil Pressure Switch from Oil Filter Mounting

Housing.

INSTALLATION

1. Install Oil Pressure Switch into Oil Filter Mounting

Housing and tighten. Tighten the screws to 30 -50Nm

(3.1 -5.1kgf⋅m).

2. Connect electrical connector.

3. Connect battery negative cable.

FUEL METERING SYSTEM

ACCELERATO R CABLE ASSEMBLY

REMOVAL

1. Loosen the adjusting nut on the cable bracket mounting

on the throttle body.

2. Remove the cable clip from holding bracket.

3. Remove accelerator control cable (on the throttle valve

end).

4. Remove the accelerator control cable (on the accelerator

pedal end).

5. Remove the grommet.

6. Remove the accelerator control cable.

INSPECTION

Check the following items, and replace the control cable if any

abnormality is found:

•The control cable should move smoothly.

•The control cable should not be bent or kinked.

•The control cable should be free of damage and

corrosion.

INSTALLATION

1. Install the accelerator control cable.

2. Install the grommet.

3. Install the accelerator control cable on the accelerator

pedal.

4. Install the accelerator control cable on the throttle valve.

5. Install the cable clip to the holding bracket.

6. Adjust the accelerator cable. Refer to

Accelerator Cable Adjustment Section.

ACCELERATO R CABLE ADJUSTMENT

ADJUSTMENT

1. Loosen the adjusting nut.

2. Loosen the jam nut.

3. Pull the outer cable while fully closing the throttle valve.

4. Tighten the adjusting nut.

5. Tighten the jam nut.

6. Loosen the adjusting nut and adjust clearance between

adjusting nut and bracket to 2∼3.5mm.

7. Tighten the jam nut again.

8. Manually operate valve.

IMPORTANT: The valve lever must return up to the stopper

screw. If the valve lever does not reach the stopper screw,

repeat the procedure again from Step 1.

ACCELERATO R PEDAL REPLACEMENT

REMOVAL

1. Disconnect the accelerator pedal control cable from the

accelerator pedal assembly.

2. Remove the two screws retaining the accelerator pedal

to the bulkhead.

3. Remove the accelerator pedal from the bulkhead.

INSTALLATION

1. Install the accelerator pedal assembly to the bulkhead

with two screws.

2. Connect the accelerator control cable to the accelerator

pedal assembly.

3. Adjust accelerator cable if necessary. Refer to

Accelerator Control Cable Adjustment Section.

FUEL FILLER CAP

The Fuel Filler Cap includes a vacuum valve. If high vacuum

occurs in the fuel tank, the vacuum valve works to adjust the

pressure in order to prevent damage to the tank.

INSPECTION

Notice: Replace the fuel filler cap with the same type of filler

cap that was originally installed on the vehicle.

•Check the seal ring in the filler cap for any abnormality

and for seal condition.

•Replace the filler cap if any abnormality is found.

WARNING

REMOVE SLOWLY

FUEL SPRAY MAY

CAUSE INJURY

FUEL FILTER

REMOVAL

1. Disconnect the negative battery cable.

2. Remove the fuel filler cap.

3. Disconnect the fuel line from the fuel filter on the engine

side.

4. Disconnect the fuel line from the fuel filter on the fuel

tank side.

5. Remove the bolt on the fuel filter holder.

6. Remove the fuel filter.

INSPECTION

1. Replace the fuel filter when the following occur:

•Fuel leaks from the fuel filter body

•The fuel filter body is damaged

•The fuel filter is clogged with dirt or sediment

2. If the drain hole is clogged with dust, clean the drain hole

with air.

INSTALLATION

1. Install the fuel filter in the correct direction.

2. Install the bolt on the fuel filter holder.

3. Connect the fuel line on the engine side.

4. Connect the fuel line on the fuel tank side.

5. Install the fuel filler cap.

6. Connect the negative battery cable.

FUEL INJECTORS

REMOVAL

Notice: If the fuel injectors are leaking, the engine oil may be

contaminated with fuel. Check the oil for signs of

contamination and change the oil and filter if necessary.

Notice: Use care in removing the fuel injector in order to

prevent damage to the fuel injector al connector pins or fuel

injector nozzles. The fuel injector is an al component and

should not be immersed in any type of cleaner as this may

damage the fuel injector.

IMPORTANT: Fuel injectors are serviced as complete

assembly only.

1. Disconnect the negative battery cable.

2. Disconnect al connector from fuel injector.

3. Remove the fuel rail. Refer to

Fuel Rail Removal P rocedure.

4. Remove the fuel injector retainer clip.

5. Remove the fuel injector assembly from fuel rail.

6. Remove O-ring from the fuel injector.

7. Remove O-ring backup from fuel injector.

INSPECTION

1. Inspect O-ring for crack, damage or leaks.

2. Replace worn or damaged O-ring.

3. Lubricate the new O-rings with engine oil before

installation.

INSTALLATION

1. Lubricate the new O-ring with engine oil.

2. Install the O-ring backup on the fuel injector.

3. Install new O-ring on the fuel injector.

4. Install all four injector on the fuel rail.

5. Use new injector retainer clip to retain the injetor to the

fuel rail.

6. Coat the end of the fuel injector with engine oil.

7. Install fuel rail assembly . Tighten the nuts to 19 N⋅m (1.9

kgf⋅m). Refer to Fuel Rail Installation Procedure.

Tighten the flare nut to 27 - 33 N⋅m (2.8 - 3.4 kgf⋅m).

8. Connect the negative battery cable.

FUEL PRESSURE REGULATOR

REMOVAL

CAUTION: To reduce the risk of fire and personal injury, i

is necessary to relieve the fuel system pressure before

servicing the fuel system components.

CAUTION: After relieving the fuel syst em pressure, a smal

amount of fuel may be released when servicing fuel lines

or connections. Reduce the chance of personal injury b

covering the fuel line fitting with a shop towel before

disconnecting the fittings. The towel will absorb any fue

that may leak out. When the disconnect is completed,

place the towel in an approved container.

Notice: Compressed air must never be used to test or clean a

fuel pressure regulator, as damage to the fuel pressure

regulator may occur.

Notice: To prevent damage to the fuel pressure regulator, do

not immerse the pressure regulator in solvent.

1. Depressurize the fuel system. Refer to

Fuel Pressure Relief Procedure.

2. Disconnect the negative battery cable.

3. Remove the fuel pump relay.

4. Disconnect the vacuum line form fuel pressure regulator.

5. Remove the fuel pressure regulator retaining screw.

6. Remove the fuel pressure regulator from fuel rail.

INSTALLATION

1. Insert the fuel pressure regulator into the fuel rail.

2. Install the fuel pressure regulator retaining bracket and

tighten with a screw.

3. Connect vacuum line onto the fuel pressure regulator.

4. Install the fuel pump relay.

5. Connect the negative battery cable.

6. Crank the engine until it starts. Cranking the engine may

take longer than usual due to trapped air in the fuel line.

7. Tighten the flare nut to 27 - 33 N⋅m (2.8 - 3.4 kgf⋅m).

FUEL PRESSURE RELIEF

WARNING

REMOVE SLOWLY

FUEL SPRAY MAY

CAUSE INJURY

CAUTION: To reduce the risk of fire and personal injury, i

is necessary to relieve the fuel system pressure before

servicing the fuel system components.

CAUTION: After relieving the fuel syst em pressure, a smal

amount of fuel may be released when servicing fuel lines

or connections. Reduce the chance of personal injury b

covering the fuel line fitting with a short towel before

disconnecting the fittings. The towel will absorb any fue

that may leak out. When the disconnect is completed,

place the towel in an approved container.

1. Remove the fuel filler cap.

2. Remove the fuel pump relay from the underhood relay

box.

3. Start the engine and allow it to stall.

4. Crank the engine for about 30 seconds.

5. Disconnect the negative battery cable.

FUEL PUMP ASSEMBLY

REMOVAL

1. Disconnect the negative battery cable.

2. Drain all fuel from fuel tank from filler neck.

3. Remove the fuel pump relay from the fuse and relay box

at right side of engine room.

4. Remove fuel tank. Refer to

Fuel Tank Remova l Procedure.

5. Using commercially available tool, loosen the screws on

the fuel pump and remove the fuel pump from the fuel

tank.

6. Lift fuel pump to remove from fuel tank.

INSPECTION

Inspect in-tank fuel filter for tears, damage of evidence of dirt

derbris or water in the fuel. If any of these condition exist,

replace the in-tank fuel filter.

INSTALLATION

1. Insert the fuel pump assembly into fuel tank and place

them in their position.

2. Using commercially available tool, tighten the screws to

the fuel pump assembly into the fuel tank.

3. Install the fuel tank. Refer to

Fuel Tank Installation Procedure.

4. Install the fuel pump relay.

5. Connect the negative battery cable.

FUEL PUMP RELAY

REMOVAL

1. Remove the fuse and relay box cover located right side

of engine room.

2. Determine correct relay by referring to the diagram on

the cover.

3. Insert a small screwdriver or use thumb pressure to

release the retainer of the relay.

4. Pull the relay straight up and out of the fuse and relay

box.

INSTALLATION

1. Insert the relay into the correct place in the fuse and relay

box with the catch slot aligned to retainer.

2. Press down until the catch of retainer engages.

3. Install fuse and relay box cover.

FUEL RAIL ASSEMBLY

REMOVAL

Notice:

•Use care when removing the fuel rail assembly in order

to prevent damage to the injector al connector terminal

and the injector spray tips.

•Fitting should be capped and holes plugged during

servicing to prevent dirt and other contaminants from

entering open lines and passage.

IMPORTANT: An eight-digit identification number is stamped

on side of the fuel injector. Refer to this number when you

service the fuel rail or when a replacement part is required.

1. Disconnect 4 injector connectors.

2. Lift side-clip up on the fuel rail.

3. Disconnect fuel pressure regulator hose.

4. Disconnect wiring harness from the bands on the fuel

rail.

5. Remove the intake pipe.

6. Loosen flare nut.

A Lift up the injectors carefully to separate them from

intake manifold.

B Lift up the fuel rail with injectors as assembly. Do not

separate the fuel injectors from fuel rail.

C If an injector become separated from fuel rail, injector

backup O-ring and injector retainer clip must be

replaced.

D Drain residual fuel from fuel rail into an approved

container.

7. If removal of fuel pressure regulator is necessary, Refer

to Fuel Pressure Regulator Removal Procedure.

8. If removal of fuel injector is necessary, Refer to

Fuel Injectors Removal Procedure.

INSTALLATION

1. Install the fuel injectors if necessary. Refer to

Fuel Injector Installation Procedure.

2. Install the fuel pressure regulator if necessary. Refer to

Fuel Pressure Regulator Installation Procedure.

3. Place the fuel injector rail assembly on the manifold and

insert the injectors into each port by pushing fuel rail.

4. Install two fuel rail retaining bolts. Tighten fuel rail

retaining bolt to 19 N⋅m (1.9kgf⋅m)

5. Place wiring harness in its place and secure it with two

nuts.

6. Connect all connector to each fuel injector.

7. Connect the fuel supply line securely. Do not over

tighten.

8. Connect the fuel return line securely. Do not over tighten.

9. Connect the negative battery cable.

10. Crank the engine until it starts. Cranking the engine may

take longer than usual due to trapped air in the fuel

system. Check for leak. If fuel leak is observed, stop

engine immediately. Before correcting fuel leak, be sure

to depressurize system again.

FUEL TANK

REMOVAL

1. Disconnect the negative battery cable.

2. Remove fuel filler cap.

3. Drain the fuel from fuel filler neck.

4. Disconnect the fuel filler hose at the fuel tank.

5. Disconnect the air breather hose at the fuel tank.

6. Disconnect the evaporator hose at the fuel tank.

7. Hold entire fuel tank at the bottom with stands.

8. Disconnect fuel supply lines and fuel return line at near

the fuel filter inside of body frame.

9. Remove fixing bolts holding fuel tank to the frame.

10. Lower tank assembly from the vehicle a little to make

access space on top.

11. Disconnect connectors at fuel pump.

12. Remove pump tank assembly from the vehicle.

13. Remove the tank under guard to the tank.

14. Remove the tank from the guard.

INSTALLATION

1. Secure fuel tank into under guard with retaining bolts, if

necessary.

2. Place the fuel tank assembly onto stands.

3. Lift the fuel tank assembly near the position.

4. Connect connectors at fuel pump.

5. Lift the fuel pump to its position and secure it with

mounting bolts. Make sure that all hoses and fuel lines

are out of way between the fuel tank and the fuel tank

bracket. Tighten the fuel tank retaining bolts to 36 N⋅m

(3.7kgf⋅m).

6. Connect fuel supply and return lines.

7. Connect the fuel filler hose, the air breather hose and

EVAP hose onto fuel tank and secure them with clamps.

8. Pour fuel into fuel tank.

9. Install fuel filler cap securely.

10. Connect the battery negative cable.

THROTTLE BODY (TB)

REMOVAL

1. Disconnect the negative battery cable.

2. Drain the cooling system. Refer to Cooling Sys tem.

3. Remove the air intake duct. Refer to

Air Intake Duct Removal Procedure.

4. Remove the accelerator cable from throttle. Refer to

Accelerator Cable Assembly Removal Procedure.

5. Disconnect the al connectors from the throttle position

sensor and the idle air control valve solenoid.

6. Disconnect all vacuum hoses below air horn.

7. Disconnect coolant lines.

8. Remove the mounting nuts retaining the throttle body to

the intake manifold.

9. Remove the throttle body from the intake manifold.

10. Remove the gaskets from the intake manifolds.

11. Remove the IAC. Refer to

Idle Air Control Valve Solenoid Removal Procedure.

12. Remove TPS. Refer to Throttle Position Sensor

Removal Procedure.

INSPECTION

Notice: Do not use solvent of any ty pe w hen y ou clean the gasket

surfaces on the intake manifold and the throttle body assembly.

The gasket surface and the throttle body assembly may be

damaged as results.

1. If the throttle body gasket needs to be released, remove

any gasket materiel that may be stuck to the mating

surfaces of the manifold.

2. Do not leave any scratches in the aluminum casting.

INSTALLATION

1. Install IAC valve onto the throttle body. Refer to

IAC valve Installation Procedure.

2. Install TPS onto the throttle body if necessary. Refer to

TPS Installation Procedure.

3. Place the gasket then the throttle body on the manifold.

4. Install four mounting bolts. Tighten the throttle body

mounting bolt to 13.5 N⋅m (1.4kgf⋅m).

5. Connect coolant line and secure them with clamps.

6. Connect all vacuum hoses and secure them with clamps

if necessary.

7. Install accelerator control cable bracket onto the throttle

body.

8. Connect accelerator control cable to throttle plate.

9. Connect al connector at IAC valve and TPS.

10. Install the air intake duct. Refer to

Air Intake Duct Installation Procedure.

11. Fill the cooling system with required coolant. Refer to

Engine Cooling Sys tem.

12. Connect the negative battery cable.

ELECTRONIC IGNITION SYSTEM

IGNITION COIL

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect all four spark plug cables from the coil.

3. Disconnect al connector from the ignition coil.

4. Remove three mounting bolts from the ignition coil.

5. Remove the ignition coil from the bracket.

INSTALLATION

1. Install the ignition coil onto the bracket with three

mounting bolts.

2. Connect al connector at the ignition coil.

3. Connect spark plug cable to the ignition coil.

4. Connect the negative battery cable.

SPARK PLUG S

Type: RN9YC4

Spark Gap: 1.0-1.1 mm (0.039" - 0.043")

Spark Plug Torque: 25N⋅m (2.5kgf⋅m)

REMOVAL

1. Disconnect the negative battery cable.

2. Remove the spark plug cable.

3. Remove the spark plug.

INSPECTION

1. Check the insulator for cracks. Replace the spark plug if

cracks are present.

2. Check the electrode condition and replace the spark plug

if necessary.

If the spark plug electrodes and insulators are fouled with carbon

or oil, the engine will not operate efficiently.

There are a number of possible causes:

•Fuel mixture is too rich.

•Oil in the combustion chamber.

•The spark plug gap is not set correctly.

If spark plug fouling is excessive, check the fuel and al system

for possible causes of trouble. If fuel and al system are normal,

install spark plugs of a higher heat range which have the same

physical dimensions as the original equipment spark plugs.

The following symptoms are characteristics of spark plugs that

are running too hot:

•Fuel mixture is too lean.

•Heat range is incorrect.

If vehicle usage does not conform to normal driving conditions,

a more suitable spark plug may be substituted.

If fuel and al system are normal, in most cases of this sort, the

problem can be corrected by using a colder type spark plug

with the same physical dimensions as the original equipment

spark plug.

3. Check the gaskets for damage and replace if necessary.

4. Measure the spark plug gap. The specification is 1.0 to

1.1mm (0.039 to 0.043").

5. Adjust the spark gap by bending the grounded electrode.

INSTALLATION

1. Tighten the spark plug to the 25N⋅m (2.5kgf⋅m).

2. Push the spark plug cable in until it snaps in.

SPARK PLUG CABLES

The cable contains a synthetic conductor which is easily

damaged. Never stretch or kink the cable. Disconnect the

cable from spark plug and the ignition coil.

The original equipment cables and the ignition coil are marked

to show correct location of the cables. If spark plug cables or

the ignition coil are replaced previously, before cables are

removed from the ignition coil, mark the cables and the coil so

they can be reconnected in the same position.

INSPECTION

Notice: Never puncture the spark plug cable's insulation with a

needle or the pointed end of a probe into the cable. An

increase in resistance would be created which would cause the

cable to become defective.

1. If the cable has broken or cracked insulation, it must be

replaced.

2. If the terminals are corroded or loose, the cable must be

replaced.

3. Check that the cable resistance does not exceed #1 cyl.

4.7 kΩ, #2 cyl. 3.9 kΩ, #3 cyl. 3.4kΩ and #4 cyl. 3.1kΩ.

EMISSIONS

CATALYTIC CO NVERTER (IF APPLI CABLE)

Refer to Engine Exhaust.

AI R CO NDITIONING RELAY

REMOVAL

1. Remove the fuse and relay box cover at right side of

engine room.

2. Refer to the diagram on the cover to determine which is

the correct relay.

3. Insert small screwdriver or use thumb pressure to

release the retainer of the relay.

4. Pull the relay straight up and out of the fuse and relay

box.

INSTALLATION

1. Insert the relay into the correct place in the fuse and relay

box with the catch slot aligned to retainer.

2. Press down until the catch of retainer engages.

3. Install fuse and relay box cover.

IGNITION TIMING ADJUSTMENT

There is no timing adjustment. The timing signal is furnished

by the CKP, ECM control the ignition timing.

EVAP CANISTER HOSES (IF APPLI CABLE)

To see the routing of the EVAP canister hoses, refer to

Emission Control System schematics.

EVAP CANISTER (IF APPLICABLE)

REMOVAL

1. Disconnect all hoses.

2. Remove EVAP canister.

INSPECTION

1. Inspect the hoses for cracks, damage and leaks.

2. Inspect the canister for damages.

INSTALLATION

1. Install EVAP canister.

2. Connect all hoses and secure them with clamps.

EVAP CANISTER PURGE VALVE SOLENOID

(IF APPLICABLE)

REMOVAL

1. Disconnect the negative battery cable.

2. Disconnect al connector from EVAP purge solenoid

located on the intake manifold.

3. Disconnect the vacuum hoses from the solenoid.

4. Slide EVAP purge solenoid out from the bracket.

INSTALLATION

1. Insert EVAP purge solenoid valve onto the bracket.

2. Install the bracket on the intake manifold.

3. Connect vacuum hoses and al connector at the purge

valve.

WIRING AND CONNECTORS

WIRI NG HARNESS SERVI CE

The control module harness electrically connects the control

module to the various solenoids, switches and sensors in the

vehicle engine compartment and passenger compartment.

Replace wire harnesses with the proper part number

replacement.

Because of the low amperage and voltage levels utilized in

electric control systems, it is essential that all wiring in

environmentally exposed areas be repaired with crimp and

seal splice sleeves.

The following wire harness repair information is intended as a

general guideline only. Refer to Chassis Electrical for all wire

harness repair procedures.

ECM CONNECTORS AND TERMINALS

REMOVAL

1. Remove the connector terminal retainer.

2. Push the wire connected to the affected terminal through

the connector face so that the terminal is exposed.

3. Service the terminal as necessary.

INSTALLATION

1. Bend the tab on the connector to allow the terminal to be

pulled into position within the connector.

2. Pull carefully on the wire to install the connector terminal

retainer.

CONNECTORS AND TERM INALS

Use care when probing a connector and when replacing

terminals. It is possible to short between opposite terminals.

Damage to components could result. Always use jumper wires

between connectors for circuit checking. NEVER probe

through Weather-Pack seals. Use an appropriate connector

test adapter kit which contains an assortment of flexible

connectors used to probe terminals during diagnosis. Use an

appropriate fuse remover and test tool for removing a fuse and

to adapt the fuse holder to a meter for diagnosis.

Open circuits are often difficult to locate by sight because

oxidation or terminal misalignment are hidden by the

connectors. Merely wiggling a connector on a sensor, or in the

wiring harness, may temporarily correct the open circuit.

Intermittent problems may also be caused by oxidized or loose

connections.

Be certain of the type of connector/terminal before making any

connector or terminal repair. Weather-Pack and Com-Pack III

terminals look similar, but are serviced differently.

WIRE HARNESS REPAIR: TWISTED

SHIELDED CABLE

REMOVAL

1. Remove the outer jacket.

2. Unwrap the aluminum/mylar tape. Do not remove the

mylar.

3. Untwist the conductors.

4. Strip the insulation as necessary.

INSTALLATION

1. Splice the wires using splice clips and rosin core solder.

2. Wrap each splice to insulate.

3. Wrap the splice with mylar and with the drain

(uninsulated) wire.

4. Tape over the whole bundle to secure.

TWISTE D LEADS

REMOVAL

1. Locate the damaged wire.

2. Remove the insulation as required.

INSTALLATION

1. Use splice clips and rosin core solder in order to splice

the two wires together.

2. Cover the splice with tape in order to insulate it from the

other wires.

3. Twist the wires as they were before starting this

procedure.

4. Tape the wires with electrical tape.

WEATHER-PACK CONNECTOR

TOOLS REQUIRED

5-8840-0388-0 Weather-Pack II Terminal Remover

REMOVAL

A Weather-Pack connector can be identified by a rubber seal

at the rear of the connector. This engine room connector

protects against moisture and dirt, which could form oxidation

and deposits on the terminals. This protection is important,

because of the low voltage and the low amperage found in the

electronic sy stems.

1. Open the secondary lock hinge on the connector.

2. Use tool 5-8840-0388-0 or the equivalent to remove the

pin and the sleeve terminals. Push on 5-8840-0388-0 to

release.

Notice: Do not use an ordinary pick or the terminal may be

bent or deformed. Unlike standard blade terminals, these

terminals cannot be straightened after they have been

improperly bent.

3. Cut the wire immediately behind the cable seal.

INSTALLATION

Make certain the connectors are properly seated and all of the

sealing rings are in place when you reconnect the leads. The

secondary lock hinge provides a backup locking feature for the

connector. The secondary lock hinge is used for added

reliability. This flap should retain the terminals even if the small

terminal lock tangs are not positioned properly.

Do not replace the Weather-Pack connections with standard

connections. Read the instructions provided with the Weather-

Pack connector and terminal packages.

1. Replace the terminal.

2. Slip the new seal onto the wire.

3. Strip 5mm (0.2”) of insulation from the wire.

4. Crimp the terminal over the wire and the seal.

5. Push the terminal and the connector to engage the

locking tangs.

6. Close the secondary locking hinge.

COM- PACK III

The Com-Pack III terminal looks similar to some Weather-

Pack terminals. This terminal is not sealed and is used where

resistance to the environment is not required. Use the standard

method when repairing a terminal. Do not use the Weather-

Pack terminal tool 5-8840-0388-0 or equivalent. These will

damage the terminals.

METRI-PACK

TOOLS REQUIRED

5-8840-0632-0 Terminal Remover

REMOVAL

Some connectors use terminals called Metri-Pack Series 150.

These may be used at the engine coolant temperature (ECT)

sensor.

1. Slide the seal (1) back on the wire.

2. Insert the 5-8840-0632-0 tool or equivalent (3) in order to

release the terminal locking tang (2).

3. Push the wire and the terminal out through the

connector. If you reuse the terminal, reshape the locking

tang.

INSTALLATION

Metri-Pack terminals are also referred to as "pull-to-seat"

terminals.

1. In order to install a terminal on a wire, the wire must be

inserted through the seal (2) and through the connector

(3).

2. The terminal (1) is then crimped onto the wire.

3. Then the terminal is pulled back into the connector to

seat it in place.

GENERAL DESCRIPTION

ECM AND SENSORS

58X REFERENCE ECM INPUT

The engine control module (ECM) uses this signal from the

crankshaft position (CKP) sensor to calculate engine RPM and

crankshaft position at all engine speeds. The ECM also uses

the pulses on this circuit to initiate injector pulses. If the ECM

receives a number of pulses other than the expected amount,

DTC 19, will set. The engine will not start and run without using

the 58X reference signal.

A/C REQUEST SIGNAL

This signal tells the ECM when the A/C mode is selected at the

A/C control switch. The ECM uses this signal to adjust the idle

speed before turning ON the A/C clutch. The A/C compressor

will be inoperative if this signal is not available to the ECM.

Refer to A/C Clutch Circuit Diagnosis for A/C wiring

diagrams and diagnosis for the A/C electrical system.

CRANKSHAFT POSITION ( CKP) SENSOR

The crankshaft position (CKP) sensor provides a signal used

by the engine control module (ECM) to calculate the ignition

sequence and ECM uses this signal as a trigger for fuel

injection timing and spark timing. The CKP sensor initiates the

58X reference pulses which the ECM uses to calculate RPM

and crankshaft position.

Refer to Electronic Ignition System for additional information.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

The engine coolant temperature (ECT) sensor is a thermistor

(a resistor which changes value based on temperature)

mounted in the engine coolant stream. Low coolant

temperature produces a high resistance of about 100,000

ohms at −40°C (−40°F). High temperature causes a low

resistance of about 70 ohms at 130°C (266°F).

The ECM supplies a 5-volt signal to the ECT sensor through

resistors internal to the ECM and then measures the voltage

after the internal resistor. This signal voltage will be high when

the engine is cold and low when the engine is hot. By

measuring the voltage, the ECM calculates the engine coolant

temperature. Engine coolant temperature affects most of the

systems that the ECM controls.

The Scan Tool displays engine coolant temperature in

degrees. After engine start-up, the temperature should rise

steadily to about 92°C (197°F). It then stabilizes when the

thermostat opens. If the engine has not been run for several

hours (overnight), the engine coolant temperature and intake

air temperature displays should be close to each other. A hard

fault in the engine coolant sensor circuit will set DTC 14 or 15.

FUEL CONTROL HEATED OXYGEN SENSOR

(IF APPLICABLE)

The fuel control heated oxygen sensor is mounted in the

exhaust stream where it can monitor the oxygen content of the

exhaust gas. The oxygen present in the exhaust gas reacts

with the sensor to produce a voltage output. This voltage

should constantly fluctuate from approximately 60mV to

900mV. The heated oxygen sensor voltage can be monitored

with a Scan Tool. By monitoring the voltage output of the

oxygen sensor, the ECM calculates the pulse width command

for the injectors to produce the proper combustion chamber

mixture.

•Low HO2S voltage is a lean mixture which will result in a rich

command to compensate.

•High HO2S voltage is a rich mixture which will result in a

lean command to compensate.

When HO2S is not ready for use as a feedback for fuel control

system, Diagnostic Trouble Code 13 will be set and the scan

tool will display a voltage between 340mv and 540mv.

INTAKE AIR TEMPERATURE (IAT) SENSOR

The intake air temperature (IAT) sensor is a thermistor which

changes its resistance based on the temperature of air

entering the engine. Low temperature produces a high

resistance of about 100,000 ohms at −40°C (−40°F). High

temperature causes low resistance of about 70 ohms at 130°C

(266°F). The ECM supplies a 5-volt signal to the sensor

through a resistor internal to the ECM, and then monitors the

signal voltage. The voltage will be high when the incoming air

is cold. The voltage will be low when the incoming air is hot. By

measuring the voltage, the ECM calculates the incoming air

temperature. the IAT sensor signal is used to adjust spark

timing according to the incoming air density.

The Scan Tool displays the temperature of the air entering the

engine. The temperature should read close to the ambient air

temperature when the engine is cold and rise as underhood

temperature increases. If the engine has not been run for

several hours (overnight), the IAT sensor temperature and

engine coolant temperature should read close to each other. A

failure in the IAT sensor circuit will set DTC 69 or DTC 71.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

The MAP sensor responds to changes in intake manifold

pressure (vacuum). the MAP sensor signal voltage to the ECM

varies from below 2 volts at idle (high vacuum) to above 4 volts

with the ignition ON, engine not running or at wide-open throttle

(low vacuum).

The MAP sensor is used to determine the following.

•Engine vacuum level for other diagnostics.

•Barometric pressure (BARO).

If the ECM detects a voltage that is lower than the possible

range of the MAP sensor, DTC 34 will be set. A signal voltage

higher than the possible range of the sensor will DTC 33.

ENGINE CO NTROL MODULE (ECM)

The engine control module (ECM) is located in the passenger

compartment at the Instrument panel lower center cover

assembly. The ECM controls the following:

•Fuel metering system.

•Ignition timing.

•On-board diagnostics for electrical functions.

The ECM constantly observes the information from various

sensors. The ECM controls the systems that affect vehicle

performance. The ECM performs the diagnostic function of the

system. It can recognize operational problems, alert the driver

through the Check Engine lamp, and store diagnostic trouble

codes (DTCs). DTCs identify the problem areas to aid the

technician in making repairs.

ECM FUNCTION

The ECM supplies either 5 or 12 volts to power various

sensors or switches. The power is supplied through resistors in

the ECM which are so high in value that a test light will not light

when connected to the circuit. In some cases, even an ordinary

shop voltmeter will not give an accurate reading because its

resistance is too low. Therefore, a digital voltmeter with at least

10 megohms input impedance is required to ensure accurate

voltage readings. Tool 5-8840-2392-0 meets this requirement.

The ECM controls output circuits such as the injectors, IAC,

etc., by controlling the ground or the power feed circuit through

transistors or through either of the following two devices:

•Output Driver Module (ODM)

•Quad Driver Module (QDM)

ECM COM PONENTS

The ECM is designed to maintain exhaust emission levels to

government mandated standards while providing excellent

driveability and fuel efficiency. The ECM monitors numerous

engine and vehicle functions via electronic sensors such as the

throttle position sensor (TPS), heated oxygen sensor (HO2S) if

applicable, and vehicle speed sensor (VSS). The ECM also

controls certain engine operations through the following:

•Fuel injector control

•Ignition control module

•Evaporative emission (EVAP) purge

•A/C clutch control

ECM VOLTAGE DESCRIPTION

The ECM supplies a buffered voltage to various switches and

sensors. It can do this because resistors in the ECM which are

so high in value that a test light may not illuminate when

connected to the circuit. An ordinary shop voltmeter may not

give an accurate reading because the voltmeter input

impedance is too low. Use a 10-megohm input impedance

digital voltmeter (such as 5-8840-2392-0) to assure accurate

voltage readings.

The input/output devices in the ECM include analog-to-digital

converters, signal buffers, counters, and special drivers. The

ECM controls most components with electronic switches which

complete a ground circuit when turned "ON." These switches

are arranged in groups of 4, called a quad driver module

(QDM), which can independently control up to 4 output.

ECM INPUTS/OUTPUTS

INPUTS - OPERATING CONDITIONS READ

•Air Conditioning Compressor Clutch ON or OFF

•Engine Coolant Temperature

•Crankshaft Position

•Exhaust Oxygen Content (If equipped)

•Manifold Abso lute Pressure

•Battery Voltage

•Throttle Position

•Knock

•Vehicle Speed

•Fuel Pump Voltage

•Power Steering Pressure

•Intake Air Temperature

OUTPUTS - SYSTEMS CONTROLLED

•EVAP Canister Purge Control Solenoid Valve

•Ignition Control

•Fuel Injector Control

•Idle Air Control

•Electric Fuel Pump Relay

•Air Conditioning Compressor Clutch Relay

•Diagnostics

- OBD Malfunction Indicator Lamp (Check Engine lamp)

- Data Link Connector (DLC)

- Data Output

•Tachometer Signal

ECM SERVICE PRECAUTIONS

The ECM is designed to withstand normal current draws

associated with vehicle operation. Avoid overloading any

circuit. When testing for opens and shorts, do not ground or

apply voltage to any of the ECM's circuits unless instructed to

do so. These circuits should only be tested using digital

voltmeter 5-8840-2392-0. The ECM should remain connected

to the ECM or to a recommended breakout box.

THROTTLE POSITION SENSOR (TPS)

The throttle position sensor (TPS) is a potentiometer

connected to the throttle shaft on the throttle body. The ECM

monitors the voltage on the signal line and calculates throttle

position. As the throttle valve angle is changed (accelerator

pedal moved), the TPS signal also changes. At a closed

throttle position, the output of the TPS is about 0.25 Volts. As

the throttle valve opens, the output increases so that at wide

open throttle (WOT), the output voltage should be about 4.75

volts.

The ECM calculates fuel delivery based on throttle valve angle

and manifold pressure for fuel delivery under the most

circumstances. A broken or loose TPS may cause intermittent

bursts of fuel from an injector and unstable idle because the

ECM thinks the throttle is moving. A hard failure in the TPS 5-

volt reference or signal circuits will set either a DTC21 or 22. If

ECM detects a low impedance short to ground in the TPS

circuit, Diagnostic Trouble code 22 will be set.

If ECM detects a low impedance short to battery in the TPS

circuit, Diagnostic Trouble Code 21 will be set.

VEHICLE SPEED SENSOR ( VSS)

The ECM determines the speed of the vehicle by converting a

pulsing voltage signal from the vehicle speed sensor (VSS)

into km per hour. The ECM uses this signal to operate the

speedometer.

USE OF CIRCUIT TESTING TOOLS

Do not use a test light to diagnose the electic electrical system

unless specifically instructed by the diagnostic procedures. Use

Connector Test Adapter Kit 5-8840-0385-0 whenever

diagnostic procedures call for probing connectors.

AFTERMARKET ELECTRICAL AND VACUUM

EQUIPMENT

Aftermarket (add-on) electrical and vacuum equipment is

defined as any equipment which connects to the vehicle's

electrical or vacuum systems that is installed on a vehicle after

it leaves the factory. No allowances have been made in the

vehicle design for this type of equipment.

Notice: No add-on vacuum equipment should be added to this

vehicle.

Notice: Add-on electrical equipment must only be connected

to the vehicle's electrical system at the battery (power and

ground).

Add-on electrical equipment, even when installed to these

guidelines, may still cause the electric system to malfunction.

This may also include equipment not connected to the vehicle

electrical system such as portable telephones and radios.

Therefore, the first step in diagnosing any electric problem is to

eliminate all aftermarket electrical equipment from the vehicle.

After this is done, if the problem still exists, it may be

diagnosed in the normal manner.

ELECTROSTATIC DISCHARGE DAMAGE

Electronic components used in the ECM are often designed to

carry very low voltage. Electronic components are susceptible

to damage caused by electrostatic discharge. Less than 100

volts of static electricity can cause damage to some electronic

components. By comparison, it takes as much as 4000 volts

for a person to feel even the zap of a static discharge.

There are several ways for a person to become statically

charged. The most common methods of charging are by

friction and induction.

•An exam ple of c harging by friction is a person sliding acros s

a vehicle seat.

•Charge by induction occurs when a person with well-

insulated shoes stands near a highly charged object and

momentarily touches ground. Charges of the same polarity

are drained off leaving the person highly charged with the

opposite polarity. Static charges can cause damage,

therefore it is important to use care when handling and

testing electronic components.

Notice: To prevent possible electrostatic discharge damage,

follow these guidelines:

•Do not touch the ECM connector pins or soldered

components on the ECM circuit board.

•Do not touch any electronic module component leads.

•Do not open the replacement part package until the part is

ready to be installed.

•Before removing the part from the package, ground the

package to a known good ground on the vehicle.

•If the part has been handled while sliding across the seat,

while sitting down from a standing position, or while walking

a distance, touc h a known good ground before installing the

part.

AI R INDUCTION

AI R INDUCTION SYSTEM

The air induction system filters contaminants from the outside air,

and directs the progress of the air as it is drawn into the engine. A

remote-mounted air cleaner prevents dirt and debris in the air from

entering the engine. The air duct assembly routes filtered air to the

throttle body. Air enters the engine by the following steps:

1. Through the throttle body.

2. Into the intake manifold.

3. Through the cylinder head intake ports.

4. Into the cylinders.

FUEL METERING

ACCELERATION MODE

The ECM provides extra fuel when it detects a rapid increase

in the throttle position and the air flow.

ACCELERATOR CONTROLS

the accelerator control system is a cable-type system with

specific linkage adjustments.

Refer to Cable Adjustment.

BATTERY VOLTAGE CORRECTION MODE

When battery voltage is low, the ECM will compensate for the

weak spark by increasing the following:

•The amount of fuel delivered.

•The idle RPM.

CLEAR FLOOD MODE

Clear a flooded engine by pushing the accelerator pedal down

all the way. The ECM then de-energizes the fuel injectors. The

ECM holds the fuel injectors de-energized as long as the

throttle remains above 75% and the engine speed is below 800

RPM. If the throttle position becomes less than 75%, the ECM

again begins to pulse the injectors ON and OFF, allowing fuel

into the cylinders.

DECELERATION FUEL CUTOFF (DFCO) M ODE

The ECM reduces the amount of fuel injected when it detects a

decrease in the throttle position and the air flow. When

deceleration is very fast, the ECM may cut off fuel completely.

Until enable conditions meet the engine revolution less 1000

rpm or manifold absolute pressure less than 10 kpa.

ENGINE SPEED/ VEHICLE SPEED/

FUEL DISABLE MODE

The ECM monitors engine speed. It turns off the fuel injectors

when the engine speed increases above 6000 RPM. The fuel

injectors are turned back on when engine speed decreases

below 3500 RPM.

FUEL CUTOFF MODE

No fuel is delivered by the fuel injectors when the ignition is

OFF. This prevents engine run-on. In addition, the ECM

suspends fuel delivery if no reference pulses are detected

(engine not running) to prevent engine flooding.

FUEL INJECTOR

The group fuel injection fuel injector is a solenoid-operated

device controlled by the ECM. The ECM energizes the

solenoid, which opens a valve to allow fuel delivery.

The fuel is injected under pressure in a conical spray pattern at

the opening of the intake valve. Excess fuel not used by the

injectors passes through the fuel pressure regulator before

being returned to the fuel tank.

A fuel injector which is stuck partly open will cause a loss of

fuel pressure after engine shut down, causing long crank

times.

FUEL METERING SYSTEM CO MPONENTS

The fuel metering system is made up of the following parts:

•The fuel injectors.

•The throttle body.

•The fuel rail.

•The fuel pressure regulator.

•The ECM.

•The crankshaft position (CKP) sensor.

•The idle air control (IAC) valve.

•The fuel pump.

•The fuel pump relay.

BASI C SYSTEM O PERATION

The fuel metering system starts with the fuel in the fuel tank.

An electric fuel pump, located in the fuel tank, pumps fuel to

the fuel rail through an in-line fuel filter. The pump is designed

to provide fuel at a pressure above the pressure needed by the

injectors. A fuel pressure regulator in the fuel rail keeps fuel

available to the fuel injectors at a constant pressure. A return

line delivers unused fuel back to the fuel tank. Refer to

Section 8A for further information on the fuel tank, line filter,

and fuel pipes.

FUEL METERING SYSTEM PURPO SE

The basic function of the air/fuel metering system is to control

the air/fuel delivery to the engine. Fuel is delivered to the

engine by individual fuel injectors mounted in the intake

manifold near each intake valve.

Following are applicable to the vehicle with closed Loop

System:

The ECM monitors signals from several sensors in order to

determine the fuel needs of the engine. Fuel is delivered under

one of several conditions called "modes." All modes are

controlled by the ECM.

The main control sensor is the heated oxygen sensor (HO2S)

located in the exhaust system. The HO2S tells the ECM how

much oxygen is in the exhaust gas. The ECM changes the

air/fuel ratio to the engine by controlling the amount of time that

the fuel injector is ON. The best mixture to minimize exhaust

emissions is 14.7 parts of air to 1 part of gasoline by weight,

which allows the catalytic converter to operate most efficiently.

Because of the constant measuring and adjusting of the

air/fuel ratio, the fuel injection system is called a "closed loop"

system.

FUEL PRESSURE REGULATOR

The fuel pressure regulator is a diaphragm-operated relief

valve mounted on the fuel rail with fuel pump pressure on one

side and manifold pressure on the other side. The fuel

pressure regulator maintains the fuel pressure available to the

injector at three times barometric pressure adjusted for engine

load. It may be serviced separately.

If the pressure is too low, poor performance and a DTC 44, will

be the result. If the pressure is too high, a DTC 45 will be the

result. Refer to Fuel System Diagnosis for information on

diagnosing fuel pressure conditions.

FUEL PUMP ELECTRICAL CIRCUIT

When the key is first turned ON, the ECM energizes the fuel

pump relay for two seconds to build up the fuel pressure

quickly. If the engine is not started within two seconds, the

ECM shuts the fuel pump off and waits until the engine is

cranked. When the engine is cranked and the 58X crankshaft

position signal has been detected by the ECM, the ECM

supplies 12 volts to the fuel pump relay to energiz e the electric

in-tank fuel pump.

An inoperative fuel pump will cause a "no-start" condition. A

fuel pump which does not provide enough pressure will result

in poor performance.

FUEL RAIL

The fuel rail is mounted to the top of the engine and distributes

fuel to the individual injectors. Fuel is delivered to the fuel inlet

tube of the fuel rail by the fuel lines. The fuel goes through the

fuel rail to the fuel pressure regulator. The fuel pressure

regulator maintains a constant fuel pressure at the injectors.

Remaining fuel is then returned to the fuel tank.

IDLE AIR CONTROL (IAC) VALVE

The purpose of the idle air control (IAC) valve is to control

engine idle speed, while preventing stalls due to changes in

engine load. The IAC valve, mounted in the throttle body,

controls bypass air around the throttle plate. By moving the

conical valve (pintle) in (to decrease air flow) or out (to

increase air flow), a controlled amount of air can move around

the throttle plate. If the RPM is too low, the ECM will retract the

IAC pintle, resulting in more air moving past the throttle plate to

increase the RPM. If the RPM is too high, the ECM will extend

the IAC pintle, allowing less air to move past the throttle plate,

decreasing the RPM.

The IAC pintle valve moves in small steps called counts.

During idle, the proper position of the IAC pintle is calculated

by the ECM based on battery voltage, coolant temperature,

engine load, and engine RPM. If the RPM drops below a

specified value, and the throttle plate is closed, the ECM

senses a near-stall condition. The ECM will then calculate a

new IAC pintle valve position to prevent stalls.

If the IAC valve is disconnected and reconnected with the

engine running, the idle RPM will be wrong. In this case, the

IAC must be reset. The IAC resets when the key is cycled on

ON then OFF. When servicing the IAC, it should only be

disconnected or connected with the ignition OFF.

The position of the IAC pintle valve affects engine start-up and

the idle characteristics of the vehicle. When the ECM detects

the 175 rpm higher engine revolution than desires engine rpm,

this malfunction detects an error in the IAC control logic.

Diagnostic Trouble code 35 will be set.

RUN MODE ( APPLICABLE TO

CLOSED LOOP SYSTEMS)

The run mode has the following two conditions:

•Open loop

•Closed loop

When the engine is first started, the system is in "open loop"

operation. In "Open Loop," the ECM ignores the signal from

the heated oxygen sensor (HO2S). It calculates the air/fuel

ratio based on inputs from the TP, ECT, and MAP sensors.

The system remains in "Open Loop" until the following

conditions are met:

•The HO2S has a varying voltage output showing that it is hot

enough to operate properly (this depends on temperature).

•The ECT has reached a specified temperature.

•A specific amount of time has elapsed since starting the

engine.

•Engine speed has been greater than a specified RPM since

start-up.

The specific values for the above conditions vary with different

engines and are stored in the programmable read only memory

(PROM). When these conditions are met, the system enters

"closed loop" operation. In "closed loop," the ECM calculates

the air/fuel ratio (injector on-time) based on the signal from the

HO2S. This allows the air/fuel ratio to stay very close to 14.7:1.

STARTING MODE

When the ignition is first turned ON, the ECM energizes the

fuel pump relay for two seconds to allow the fuel pump to build

up pressure. The ECM then checks the engine coolant

temperature (ECT) sensor and the throttle position (TP) sensor

to determine the proper air/fuel ratio for starting.

The ECM controls the amount of fuel delivered in the starting

mode by adjusting how long the fuel injectors are energized by

pulsing the injectors for very short times.

THROTTLE BODY UNIT

The throttle body has a throttle plate to control the amount of

air delivered to the engine. The TP sensor and IAC valve are

also mounted on the throttle body.

Vacuum ports located behind the throttle plate provide the

vacuum signals needed by various components. Engine

coolant is directed through a coolant cavity in the throttle body

to warm the throttle valve and to prevent icing.

ELECTRONIC IGNITION SYSTEM

CRANKSHAFT POSITION (CKP) SENSOR

The crankshaft position (CKP) sensor provides a signal used

by the engine control module (ECM) to calculate the ignition

sequence. The sensor initiates the 58X reference pulses which

the ECM uses to calculate RPM and crankshaft position. Refer

to Electronic Ignition System for additional information.

ELECTRONIC IGNITION

The electronic ignition system controls fuel combustion by

providing a spark to ignite the compressed air/fuel mixture at

the correct time. The provide optimum engine performance,

fuel economy, and control of exhaust emissions, the ECM

controls the spark advance of the ignition system. Electronic

ignition has the following advantages over a mechanical

distributor system:

•No moving parts.

•Less maintenance.

•Remote mounting capability.

•No mechanical load on the engine.

•More coil cool down time between firing events.

•Elimination of mechanical timing adjustments.

•Increased available ignition coil saturation time.

IGNITION COILS

The all engines use 2 ignition coils, 1 per 2 cylinders. A two-

wire connector provides a 12-volt primary supply through the

15-amp ignition coil fuse.

IGNITION CONTROL

The ignition control (IC) spark timing is the ECM's method of

controlling the spark advance and the ignition dwell.

The IC spark advance and the ignition dwell are calculated by

the ECM using the following inputs:

•Engine speed.

•Crankshaft position (58X reference).

•Engine coolant temperature (ECT) sensor.

•Throttle position (TP) sensor.

•Vehicle speed (vehicle speed sensor).

•ECM and ignition system supply voltage.

IGNITION CONTROL ECM OUTPUT

Ignition Coil works to generate only the secondary voltage be

receiving the primary voltage from ECM.

The primary voltage is generated at the coil driver located in

the ECM. The coil driver generate the primary voltage based

on the X58 signal. In accordance with the X58 signal, ignition

coil driver determines the adequate ignition timing and also

cylinder number to ignite.

Ignition timing is determined the Coolant Temp., Intake Air

Temp., Engine Speed, Engine Load, knock Sensor Signal, etc.

ENGINE CO NTROL MODULE (ECM)

The ECM is responsible for maintaining proper spark and fuel

injection timing for all driving conditions. To provide optimum

driveability and emissions, the ECM monitors the input signals

from the following components in order to calculate spark

timing:

•Engine coolant temperature (ECT) sensor.

•Intake air temperature (IAT) sensor.

•Throttle position sensor (TPS).

•Vehicle speed sensor (VSS).

•Crankshaft position (CKP) sensor.

SPARK PLUG

Although worn or dirty spark plugs may give satisfactory

operation at idling speed, they frequently fail at higher engine

speeds. Faulty spark plugs may cause poor fuel economy,

power loss, loss of speed, hard starting and generally poor

engine performance. Follow the scheduled maintenance service

recommendations to ensure satisfactory spark plug

performance. Refer to Maintena nce and Lubric ation.

Normal spark plug operation will result in brown to grayish-tan

deposits appearing on the insulator portion of the spark plug. A

small amount of red-brown, yellow, and white powdery material

may also be present on the insulator tip around the center

electrode. These deposits are normal combustion by-products

of fuels and lubricating oils with additives. Some electrode

wear will also occur. Engines which are not running properly

are often referred to as "misfiring." This means the ignition

spark is not igniting the air/fuel mixture at the proper time.

While other ignition and fuel system causes must also be

considered, possible causes include ignition system conditions

which allow the spark voltage to reach ground in some other

manner than by jumping across the air gap at the tip of the

spark plug, leaving the air/fuel mixture unburned. Misfiring may

also occur when the tip of the spark plug becomes overheated

and ignites the mixture before the spark jumps. This is referred

to as "pre-ignition."

Spark plugs may also misfire due to fouling, excessive gap, or

a cracked or broken insulator. If misfiring occurs before the

recommended replacement interval, locate and correct the

cause.

Carbon fouling of the spark plug is indicated by dry, black

carbon (soot) deposits on the portion of the spark plug in the

cylinder. Excessive idling and slow speeds under light engine

loads can keep the spark plug temperatures so low that these

deposits are not burned off. Very rich fuel mixtures or poor

ignition system output may also be the cause. Refer to

DTC 45.

Oil fouling of the spark plug is indicated by wet oily deposits on

the portion of the spark plug in the cylinder, usually with little

electrode wear. This may be caused by oil during break-in of

new or newly overhauled engines. Deposit fouling of the spark

plug occurs when the normal red-brown, yellow or white

deposits of combustion by-products become sufficient to cause

misfiring. In some cases, these deposits may melt and form a

shiny glaze on the insulator around the center electrode. If the

fouling is found in only one or two cylinders, valve stem

clearances or intake valve seals may be allowing excess

lubricating oil to enter the cylinder, particularly if the deposits

are heavier on the side of the spark plug facing the intake

valve.

Excessive gap means that the air space between the center

and the side electrodes at the bottom of the spark plug is too

wide for consistent firing. This may be due to improper gap

adjustment or to excessive wear of the electrode during use. A

check of the gap size and comparison to the gap specified for

the vehicle in Maintenance and Lubrication will tell if the gap is

too wide. A spark plug gap that is too small may cause an

unstable idle condition. Excessive gap wear can be an

indication of continuous operation at high speeds or with

engine loads, causing the spark to run too hot. Another

possible cause is an excessively lean fuel mixture.

Low or high spark plug installation torque or improper seating

can result in the spark plug running too hot and can cause

excessive center electrode wear. The plug and the cylinder

head seats must be in good contact for proper heat transfer

and spark plug cooling. Dirty or damaged threads in the head

or on the spark plug can keep it from seating even though the

proper torque is applied. Once spark plugs are properly

seated, tighten them to the torque shown in the Specifications

Table. Low torque may result in poor contact of the seats due

to a loose spark plug. Over tightening may cause the spark

plug shell to be stretched and will result in poor contact

between the seats. In extreme cases, exhaust blow-by and

damage beyond simple gap wear may occur.

Cracked or broken insulators may be the result of improper

installation, damage during spark plug re-gapping, or heat

shock to the insulator material. Upper insulators can be broken

when a poorly fitting tool is used during installation or removal,

when the spark plug is hit from the outside, or is dropped on a

hard surface. Cracks in the upper insulator may be inside the

shell and not visible. Also, the breakage may not cause

problems until oil or moisture penetrates the crack later.

A broken or cracked lower insulator tip (around the center

electrode) may result from damage during re-gapping or from

"heat shock" (spark plug suddenly operating too hot).

•Damage during re-gapping can happen if the gapping tool is

pushed against the center electrode or the insulator around

it, causing the insulator to crack. When re-gapping a spark

plug, make the adjustment by bending only the ground side

terminal, keeping the tool clear of other parts.

•"Heat shock" breakage in the lower insulator tip generally

occurs during several engine operating conditions (high

speeds or heavy loading) and may be caused by over-

advanced timing or low grade fuels. Heat shock refers to a

rapid increase in the tip temperature that causes the

insulator material to crack.

Spark plugs with less than the recommended amount of

service can sometimes be cleaned and re-gapped, then

returned to service. However, if there is any doubt about the

serviceability of a spark plug, replace it. Spark plugs with

cracked or broken insulators should always be replaced.

A/ C CLUTCH DIAGNOSIS

A/ C CLUTCH CIRCUIT OPERATION

A 12-volt signal is supplied to the A/C request input of the ECM

when the A/C is selected through the A/C control switch.

The A/C compressor clutch relay is controlled through the

ECM. This allows the ECM to modify the idle air control

position prior to the A/C clutch engagement for better idle

quality. If the engine operating conditions are within their

specified calibrated acceptable ranges, the ECM will enable

the A/C compressor relay. This is done by providing a ground

path for the A/C relay coil within the ECM. When the A/C

compressor relay is enabled, battery voltage is supplied to the

compressor clutch coil.

The ECM will enable the A/C compressor clutch whenever the

engine is running and the A/C has been requested. The ECM

will not enable the A/C compressor clutch if any of the following

conditions are met:

•The engine speed is greater than 6000 RPM.

•The ECT is greater than 122°C (251°F).

•The throttle is more than 95% open.

A/ C CLUTCH CIRCUIT PURPOSE

The A/C compressor operation is controlled by the engine

control module (ECM) for the following reasons:

•It improves idle quality during compressor clutch

engagement.

•It improves wide open throttle (WOT) performance.

•It provides A/C compressor protection from operation with

incorrect refrigerant pressures.

The A/C electrical system consists of the following

components:

•The A/C control switch.

•The A/C refrigerant pressure switches.

•The A/C compressor cl utch.

•The A/C compressor clutch relay.

•The ECM.

A/C REQUEST SIGNAL

This signal tells the ECM when the A/C mode is selected at the

A/C control switch. The ECM uses this input to adjust the idle

speed before turning on the A/C clutch. The A/C compressor

will be inoperative if this signal is not available to the ECM.

Refer to A/C Clutch Circuit Diagnosis for A/C wiring

diagrams and diagnosis for the A/C electrical system.

EVAPORATIVE EMISSIO N ( EVAP) SYSTEM

(IF APPLICABLE)

EVAP EMISSION CONTROL SYSTEM PURPOSE

The basic evaporative emission (EVAP) control system used

on all vehicles is the charcoal canister storage method.

Gasoline vapors from the fuel tank flow into the canister

through the inlet labeled "TANK." These vapors are absorbed

into the activated carbon (charcoal) storage device (canister) in

order to hold the vapors when the vehicle is not operating. The

canister is purged by ECM control when the engine coolant

temperature is over 60°C (140°F), the IAT reading is over 10°C

(50°F), and the engine has been running. Air is drawn into

canister through the air inlet grid. The air mixes with the vapor

and the mixture is drawn into the intake manifold.

EVAP EMISSION CONTROL SYSTEM OPERATION

The EVAP canister purge is controlled by a solenoid valve that

allows the manifold vacuum to purge the canister. The engine

control module (ECM) supplies a ground to energize the

solenoid valve (purge on). The EVAP purge solenoid control is

pulse-width modulated (PWM) (turned on and off several times

a second). The duty cycle (pulse width) is determined by

engine operating conditions including load, throttle position,

coolant temperature and ambient temperature. The duty cycle

is calculated by the ECM. the output is commanded when the

appropriate conditions have been met. These conditions are:

•The engine is fully warmed up.

•The engine has been running for a specified time.

•The IAT reading is above 10°C (50°F).

•A continuous purge condition with no purge commanded by

the ECM will set a DTC 62.

•Purge/Vacuum Hoses. Made of rubber compounds, these

hoses route the gasoline fumes from their sources to the

canister and from the canister to the intake air flow.

•EVAP Canister. Mounted on a bracket ahead of the fuel

tank, the canister stores fuel vapors until the ECM

determined that engine conditions are right for them to be

removed and burned.

Poor idle, stalling and Poor driveability can be caused by:

•A malfunctioning purge solenoid.

•A damaged canister.

•Hoses that are split, cracked, or not connected properly.

SYSTEM FAULT DETECTION

The EVAP leak detection strategy is based on applying

vacuum to the EVAP system and monitoring vacuum decay. At

an appropriate time, the EVAP purge solenoid is turned "ON,"

allowing the engine vacuum to draw a small vacuum on the

entire evaporative emission system.

After the desired vacuum level has been achieved, the EVAP

purge solenoid is turned "OFF," sealing the system. A leak is

detected by monitoring for a decrease in vacuum level over a

given time period, all other variables remaining constant.

If the desired vacuum level cannot be achieved in the test

described above, a large leak or a faulty EVAP purge control

solenoid valve is indicated.

Leaks can be caused by the following conditions:

•Missing or faulty fuel cap

•Disconnected, damaged, pinched, or blocked EVAP purge

line

•Disconnected, damaged, pinched, or blocked fuel tank

vapor line

•Disconnected or faulty EVAP purge control solenoid valve

•Open ignition feed circuit to the purge solenoid

•Damaged EVAP canister

•Leaking fuel sender assembly O-ring

•Leaking fuel tank or fuel filler neck

The ECM supplies a ground to energize the purge control

solenoid valve (purge "ON" ). The EVAP purge control is

PWM, or turned "ON" and "OFF," several times a second.

The duty cycle (pulse width) is determined by engine operating

conditions including load, throttle position, coolant temperature

and ambient temperature. The duty cycle is calculated by the

ECM and the output is commanded when the appropriate

conditions have been met.

The system checks for conditions that cause the EVAP system

to purge continuously by commanding the EVAP purge

solenoid "OFF", EVAP purge PWM "0%". If fuel tank vacuum

level increases during the test, a continuous purge flow

condition is indicated. This can be caused by the following

conditions:

•EVAP purge solenoid leaking

•EVAP purge and engine vacuum lines s witched at the EVAP

purge control solenoid valve

•EVAP purge control solenoid valve driver circuit grounded

POSITIVE CRANKCASE

VENTILATION (PCV) SYSTEM

CRANKCASE VENTI LATION SYSTEM PURPOSE

The crankcase ventilation system is used to consume

crankcase vapors in the combustion process instead of venting

them to the atmosphere. Fresh air from the throttle body is

supplied to the crankcase and mixed with blow-by gases. This

mixture is then passed through the positive crankcase

ventilation (PCV) port into the intake manifold.

While the engine is running, exhaust gases and small amounts

of the fuel/air mixture escape past the piston rings and enter

the crankcase. these gases are mixed with clean air entering

through a tube from the air intake duct.

During normal, part-throttle operation, the system is designed

to allow crankcase gases to flow through the PCV hose into

the intake manifold to be consumed by normal combustion.

A plugged positive crankcase ventilation port or PCV hose may

cause the following conditions:

•Rough idle.

•Stalling or slow idle speed.

•Oil leaks.

•Sludge in the engine.

A leaking PCV hose would cause:

•Rough idle.

•Stalling.

•High idle speed.

SPECIAL SERVICE TOOLS

LEGEND

(1) Tech 2 Scan Tool

(2) Tech 2 AC/DC Power Adapter

(3) Tech 2 OBD DLC Interface Connector

(4) Tech 2 DLC Interface Cable

(5) Tech 2 RS232 Connector Port

(6) Tech 2 10 Meg Memory Card

ITEM NO. ILLUSTRATION PART NO. PART NAME

5-8840-2392-0 High Impedance

Multimeter

(Digital Voltmeter -DVM)

5-8840-2312-0 IAC Motor Analyzer

5-8840-2618-0 Fuel Injector Tester

5-8840-0385-0 Connector Test AdapterKit

5-8840-0279-0 Vacuum Pump

with Gauge

5-8840-0632-0 Terminal Remover

5-8840-0388-0 Weather Pack

Terminal Remover

5-8840-0378-0 Pressure Gauge

5-8840-2607-0 EVAP Pressure/Purge

Diagnostic Station

ITEM NO. ILLUSTRATION PART NO. PART NAME

5-8840-2608-0 Ultrasonic Leak

Detector

5-8840-2589-0 Injector Adapter Cable

1 5-8840-2608-0 EVAP Pres sur e/Purge Diagnostic Station is a m ultipurpos e tool which is used to perf orm sever al

diagnostic procedures for enhanced emission testing. The station will accommodate a nitrogen gas filled cylinder

which is used to pressurize the vehicle EVAP system f or a leakdown test and leak loc ation tes t when a vehicle is

repaired for leakage in the enhanced evaporative emission control system. It also has two additional gauges

inches of mercury and inches of water) which are used to measure both source vacuum and EVAP canister

purge vacuum to verify correct operation and vapor flow within the canister purge circuit.

2 5-8840-2608- 0 Ultras onic Leak Detector is a micr oproc es sor -bas ed devic e us ed to detect leaks in the enhanc ed

evaporative emission control system. the evaporative system is pressurized to 30 inches of water using the

5-8840-2608-0 EVAP Pressure/Purge Diagnostic System. Small leaks in the EVAP system will emit sound at a

high frequenc y undetectable by a human ear but detec table with the 5-8840-2608-0. The technic ian tr ac es along

the evaporative system and can pinpoint leaks due to corroded lines, cracked hoses, or a damaged EVAP

com ponent. T he detector inc ludes a high quality set of headphones to block out sur rounding shop nois e and the

LED sensitivity meter allows a visual reference for locating leaks in conjunction with the audio output heard