SECTION 6C3-2 - DIAGNOSIS - GEN III V8 ENGINE

CAUTION:

This vehicle will be equipped with a Supplemental Restraint System (SRS). A SRS will consist of either

seat belt pre-tensioners and a driver's air bag, seat belt pre-tensioners and a driver's and front

passenger's air b ags o r seat b elt p re-t ension ers, driv er’s an d f ron t p asseng er’s air bag and left and right

hand side air bags. Refer to SAFETY PRECAUTIONS, Section 12M Supplemental Restraint System of the

VT Series II Service Information before performing any service operation on, or around any SRS

components, the steering mechanism or wiring. Failure to follow the SAFETY PRECAUTIONS could

result in SRS deployment, resulting in possible personal injury or unnecessary SRS system repairs.

CAUTION:

When performing any Diagnostics, make certain that the drive wh eels are blocked and the parking brake

is firmly set.

GENERAL DESCRIPTION

This is where to start all driveability and emissions diagnosis, once you read and understand Section 6C3-1

GENERAL INFORMATION of the VT Series II Service Information. The beginning of Section 6C3-2A contains

reference material: wiring diagrams, control module terminal end views, and engine component locations.

Remember, this information is for reference; do not start diagnosis using these pages. Always start diagnosis on

the page titled Powertrain OBD System Check. This check verifies that the diagnostic circuits are operating

properly, then sends you to the correct service manual page for diagnosis.

If the initial steps in the Powertrain OBD System Check reveal a problem, or if the engine does not start, you will be

using one or more tables in Section 6C3-2A of the VT Series II Service Information for diagnosis. T he Powertrain

OBD System Check will send you to the correct table. T hese tables follow the Powertrain O BD System Chec k and

problems that prevent the engine from starting.

If the Powertrain OBD System Check shows that Diagnostic Trouble Codes have been stored, proceed to the

appropriate Diagnostic Trouble Code (DTC) diagnosis pages. If m ore than one Diagnostic Trouble Code has been

stored, always start Diagnostic Trouble Code diagnosis with the lowest diagnostic trouble code number and work

upward. Diagnostic Trouble Code diagnosis pages start immediately after the diagnosis tables in Section 6C3-2A.

DIAGNOSTIC PRECAUTIONS

THE FOLLOWING REQUIREMENTS MUST BE OBSERVED WHEN WORKING ON VEHICLES.

1. Before removing any PCM system component, disconnect the battery earth lead.

2. Never start the engine without the battery being solidly connected.

3. Never separate the battery from the on board electrical system while the engine is running.

4. When charging the battery, disconnect the battery from the vehicle's electrical system.

5. Never subject the PCM to temperatures above 80° C i.e. paint oven. Always remove control unit first if this

temperature is to be exceeded.

6. Ensure that all cable harness plugs are connected solidly and that battery terminals are thoroughly clean.

7. The powertrain m anagem ent s ystem harnes s connec tors ar e designed to fit in only one way; there are indexing

tabs and slots on both halves of the connector. Forcing the connector into place is not necessary if it is being

installed with the proper orientation. Failure to take care to match the indexing tabs and slots to ensure the

connector is being installed correctly can cause damage to the connector, the module, or other vehicle

components or systems.

8. Never connect or disconnect the cable harness plug at the PCM when the ignition is switched ON.

9. Before attempting any electric Arc welding on the vehicle, disconnect the battery leads and the PCM

connectors.

10. When steam cleaning engines, do not direct the steam cleaning nozzle at PCM system components. If this

happens, corrosion of the terminals can take place.

11. Use only the test equipment specified in the diagnostic tables, since other test equipment may either give

incorrect results or damage good components.

12. All voltage m easurements using a voltmeter m ust use a digital multimeter with an internal impedance rating of

at least 10 million ohms per volt (10 mega ohms) such as the DMM J 39200.

13. When a test light is specified, a "low-power" test light must be used. Do not use a high - wattage test light.

W hile a particular brand of test light is not suggested, a simple test on any test light will ensure it to be OK for

PCM circuit testing. Connect an accurate ammeter (such as the high-impedance digital multimeter) in series

with the test light being tested, and power the test light/ammeter circuit with the vehicle battery .

If the ammeter indicates less than 3/10 amp current flow (0.3 A or 300 ma), the test light is OK to use.

If the ammeter indicates more than 3/10 amp current flow (0.3 A or 300 ma), the test light is NOT OK to use.

BATTERY

DC AMPS

BLOCKING DRIVE WHEELS

The vehicle drive wheels always should be blocked and the parking brake firmly set while checking any system.

VISUAL/PHYSICAL INSPECTION

A car ef ul vis ual and physical ins pection mus t be per f or med as par t of any diagnostic procedur e. This c an of ten lead

to fixing a problem without further steps. Inspect all the wires in the engine compartment for bad connections,

burned or chafed spots, pinched wires, or contact with sharp edges or hot exhaust manifolds. Also, inspect all the

wires. Check beneath the air cleaner, the compressor, the generator, etc. This visual/physical inspection is very

important. The inspection must be done carefully and thoroughly .

BASIC KNOWLEDGE AND TOOLS REQUIRED

To use this service manual most effectively, a general understanding of basic electrical circuits and circuit testing

tools is required. You should be familiar with wiring diagrams, the meaning of voltage, ohms, amps, the basic

theories of electricity, and understand what happens in an open or shorted circuit.

To perform system diagnosis, the following tools are required.

• A Tech 2 scan tool

• A test light

• A digital multimeter with 10 megaohms impedance

• A vacuum gauge

• A fuel pressure gauge and suitable fittings

• Fuel injector coil/ balance tester

• IAC motor analyser

Familiarise yourself with the tools and their uses before attempting diagnosis. Special tools that are required for

system se rvice and the ones described above ar e illustrated in Section 6C3- 6 SPECIAL TO OLS, of the VT Series

II Service Information.

ELECTROSTATIC DISCHARGE DAMAGE

Electronic components used to control the systems are often designed to carry very low voltage. They are very

susc eptible to damage caus ed by electrostatic dis charge. It is possible f or less than 100 volts of static electric ity to

cause damage to some 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 ways for a person to become statically charged. T he most com mon methods of charging are by

fric tion and by induction. An exam ple of c harging by friction is a pers on sliding acros s a car seat, in which a charge

of as much as 25 000 volts can build.

Charging by induction occurs when a person with well-insulated shoes stands near a highly charged object and

momentarily touches earth. Charges of the same polarity are drained off, leaving the person highly charged with

the opposite polarity. Static charges of either type can cause damage, therefore, use care when handling and

testing the electronic components.

NOTE: To prevent possible Electrostatic Discharge damage:

Do Not touch the PCM connector pins or soldered components on the PCM circuit board.

DIAGNOSTIC INFORMATION

The diagnostic tables and functional checks in this

manual are designed to locate a faulty circuit or

component through logic based on the process of

elimination. The tables are prepared with the

understanding that the vehicle:

• Functioned correctly at the time of assembly.

• There are no multiple faults.

• The problem currently exists.

The PCM/PIM performs a continual self-diagnosis

on certain control functions. This diagnostic

capability is supported by the diagnostic procedures.

The PCM/PIM indic ates the source of a fault through

the use of Diagnostic Trouble Codes (DTCs). The

DTCs are four digit (PCM will be P0XXX or P1XXX

and PIM will be B2XXX). When a fault is detected by

the PCM/PIM, a Diagnostic Trouble Code will set

and the Check Powertrain Lamp (CPL) may

illuminate.

SELF DIAGNOSTICS

The PCM/PIM per f orms s ystem s elf diagnos tic s. T he

PCM/PIM can detect and of ten isolate system faults.

When a fault is detected, the PCM/PIM sets a DTC

that represents the area of the fault. The PCM/PIM

may or may not turn ON the Check Powertrain

Lamp.(CPL)

CHECK POWERTRAIN LAMP (CPL)

This CPL is located on the instrument panel and

performs the following functions.

• T he Chec k Powertrain Lam p (CPL) is used as a

bulb check, the CPL will come ON with the

ignition ON and the engine OFF.

• The Check Powertrain Lamp (CPL) informs the

driver that a fault has occurred and that the

vehicle should be taken in for service as soon

as reasonably possible.

As a bulb and system c heck, the Check Powertrain

Lamp ( CPL) will come O N with the ignition ON and

the engine OFF. When the engine is started, the

Check Powertrain Lamp (CPL) will turn OFF. Not

all of the DTCs will turn ON the Check Powertrain

Lamp (CPL). If the Check Powertrain Lamp (CPL)

remains ON, the self-diagnostic system has

detected a problem. If the problem goes away, the

Check Powertrain Lamp (CPL) will go out in most

cases after 10 seconds but a diagnostic trouble

code will remain stored.

W hen the Check Powertrain Lamp (CPL) rem ains

ON while the engine is running, or when a fault is

suspected due to a driveability or emissions

problem, perform the "On-Board Diagnostic

System Check" Refer to POWERTRAIN OBD

SYSTEM CHECK in Section 6C3-2A of the VT

Series II Service Information. These checks will

help identify faults which may not be detected if

other diagnostics are performed.

Data Link Connector (DLC)

1. Secondary Serial Data (UART)

2. Serial Data (Class II)

4. Earth

5. Earth

6. Diagnostic Test Enable

9. Primary Serial Data (UART)

12. ABS Diagnostic Test Enable

16. Battery Voltage

INTERMITTENT CHECK POWERTRAIN (MIL)

In the case of an "intermittent" problem, the Check

Powertrain MIL may light for ten seconds and then

go out. The corresponding diagnostic trouble code

will be stored. The DTC will remain stored until the

battery voltage to the PCM has been disconnected,

or until it is erased using the Tech 2 scan tool.

When unexpected Diagnostic Trouble Codes

appear, chances are that these Diagnostic Trouble

Codes were set by an intermittent fault.

An intermittent DTC may not re-set. If an

intermittent fault occurs, do not use a Diagnostic

Trouble Code Table. Consult the "Diagnostic Aids"

on the facing page. The diagnostic table

corresponds to the intermittent Diagnostic Trouble

Code.

SYMPTOMS TABLES, Section 6C3-2B of the VT

Series II Service Information also covers the topic

of "Intermittents." A physical inspection of the

applicable sub-system most often will resolve the

problem. The Tech 2 scan tool also has several

features which can help in diagnosing intermittent

problems.

Data Link Connector (DLC) Location

1. Steering Column Lower Cover

2. Data Link Connector

3. Instrument Panel Right Hand Cover Assembly

STRATEGY BASED DIAGNOSTICS

The s tr ategy based diagnos tic is a uniform approac h to r epair all Elec tr ic al/Elect ronic (E/E) s ystems . The diagnostic

flow can always be us ed to resolve an E/E system pr oblem and is a starting point when repairs are necess ary. The

steps below are defined to ins truct the technician how to proc eed with a diagnostic process . Steps below also refer

to step numbers found on the Strategy Based Diagnostic table.

1. Verify the Driver Concern: To verify the driver concern, the technician should know the normal operation of

the system.

2. Preliminary Check:Conduct a thorough visual and operational inspection. Review the service history, detect

unusual sounds or odours, and gather Diagnostic Trouble Code information to achieve effective repair.

3. Service information (Manual) System Check(s): System checks verify proper operation of the system. This

will lead the technician in an organised approach to diagnostics.

4. Check Bulletins an d Other Service Info rmation: This should include videos, newsletters, and ser vice centre

updates.

5. Service Diagnostics (Paper/Electronic)

5.1 DTC Stored: Follow the designed DTC table exactly to make an effective repair.

5.2 Symptom, No DTC: Select the symptom from the symptom tables and follow the diagnostic paths or

suggestions to complete the repair, or refer to the applicable component/system checks in Section 6C3-

2C of the VT Series II Service Information.

5.3 No Published Diagnostics: Analyze the complaint and develop a plan for diagnostics. Utilise the

wiring diagrams and 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.

5.4 Intermittent faults: Conditions that are not always present are intermittent. To resolve intermittents,

perform the following steps:

5.4.1 Observe history DTCs, DTC modes and Freeze Frame data.

5.4.2 Evaluate the symptoms and conditions described by the driver.

5.4.3 Use a check sheet or other method to identify the circuit or electrical system component.

5.4.4 Follow the suggestions for intermittent diagnosis found in the service documentation.

The Tech 2 and DMM have data capturing capabilities that can assist in detection of intermittents.

5.5 Vehicle Operates As Designed/No Trouble Found: This condition exist when the vehicle is found to

operating normally. The condition described by the driver may be normal. Verify against another vehicle that is

operating normally. The condition m ay be intermittent. Contact Technical Assistance if the concern is com mon.

Verify the complaint under the conditions described by the driver before releasing the vehicle.

6. Re-examine the Concern: When the complaint cannot be successfully found or isolated, a reevaluation is

necessary. The complaint should be re-verified and could be intermittent or normal as per step 5.3 or 5.5.

7. Repair and Verificat ion Tests: After isolating the cause, the r epair should be m ade. Then validate f or proper

operation and verify that the symptom has been corrected. This may involve road testing or other m ethods to

verify the complaint has been resolved under the following conditions:

• Conditions noted by the driver.

• If a DTC was diagnosed, verify a repair by duplicating conditions present when a DTC was set as noted in

the Freeze Frame/Failure Records data.

STRATEGY BASED DIAGNOSTICS

VERIFY DRIVER CONCERN

PRELIMI NARY CHECKS

Visual and Operational

Perform Published

POWERTRAIN O BD SYSTEM CHECK

CHECK FOR BULLETINS

(Printed/DCS/Techline Equipment)

STORED SYMPTOM

DTC(S) NO DTC(S)

FOLLOW FOLLOW

PUBLISHED PUBLISHED

DTC SYMPTOM

DIAGNOSTICS DIAGNOSTICS

NO PUBLISHED INTERMITTENT

DIA GNOSTICS

Analyze & Develop SEE

Diagnostics or Call DIAGNOSTIC

Technical DETAILS

Assistance

5.1 5.2 5.3 5.4

OPERATING AS DESIGNED

• Driver Misunderstanding of System:

Refer to Management or Zone

• Product Problem: Call Technical

Assistance

ISOLATE THE PROBLEM

REPAIR & VERIFY FI X

RE-EXA MINE

THE CONCERN

5.5

YES

DIAGNOSTIC TROUBLE CODES

DTCs are stored with various additional information:

• History: fault has been detected by the control module, but might not be set at the moment.

• CPL or Message Requested: Check Powertrain Malfunction Indicator Lamp has been turned ON.

• Last Test Failed.

• Test Failed Since Code Cleared.

• Not Ran Since Code Cleared: controller has not tested yet if fault is active.

• Failed This Ignition.

HOW TO USE THE FREEZE FRAME / FAILURE RECORDS INFORMATION

When a PCM DTC is set, there will be a Freeze Frame/Failure Record for that DTC. The Freeze Frame/ Failure

Records data list has 32 parameters for data capture. When a DTC is set, the control module will capture all 32

parameters at the time the DTC is logged. When a technician is diagnosing a DTC, this Freeze Frame/Failure

Record information can be retrieved and reviewed to assist in diagnosis.

In addition to the regular data list parameters found in the Freeze Frame/Failure Records data list, there is

additional information available about the DTC diagnostics:

• FIRST ODOMETER - vehicle kilometre value when the DTC failure first recorded

• LAST ODOMETER - vehicle kilometere value when the DTC fail is recorded

• FAIL COUNTER - number of ignition cycles with failure (DTC was set)

• PASS COUNTER - number of ignition cycles with diagnostic passes (DTC was not set again)

• NOT RUN COUNTER - number of ignition cycles without diagnostic run (DTC conditions were not tested)

READING THE DTCS

The provision for communicating with the PCM/PIM is the Data Link Connector (DLC). The DLC is located below

the instrument panel cover assembly. The DLC connector is used in assembly plants to receive information in

checking that the engine and transmission and other sub-systems are operating properly before they leave the

plant. The Diagnostic Trouble Code(s) stored in the PCM/PIM memory can be read with a Tech 2 scan tool.

CLEARING THE DTCS

To clear a current Diagnostic Trouble Code from the memory of the PCM, the PCM power feed must be

disconnected for at least ten (10) seconds, or the Tech 2 scan tool must be used. The battery power feed can be

disconnected by:

• Disconnecting the negative battery terminal

• Removing the Fuse F31 in the engine compartment fuse/relay panel.

The Tech 2 scan tool has a special mode that can be used to clear both history and current diagnostic trouble

codes. This mode is labeled Clear DTC Information found under Diagnostic Trouble Codes.

NOTE: To prevent PCM damage, the ignition must be OFF when disconnecting or reconnecting PCM power.

CLEARING THE DTC HISTORY CODE

The Tech 2 scan tool is the only tool capable of clearing the DTC history code. Disconnecting the battery will not

erase DTC history. The Tech 2 scan tool sends a special message to the PCM to erase the DTCs.

IGNITION CYCLE DEFAULT

If the ignition is c ycled (OF F and ON) 50 tim es without a particular f ault resetting, that DT C will be cleared from the

PCM memory and the ignition cycle counter in the PCM will reset to zero.

PCM SLEEP TEST

After the ignition s witch is turned OFF the PCM will continue to operate for several sec onds. During this shut down,

the PCM will set the IAC valve to a position to be used on the next startup, de-energising all the solenoids and

relays, etc. and go to sleep. The Tech 2 scan tool will display updated data until the sleep mode is activated then

the PCM will no longer send out serial data and the Tech 2 scan tool will display DLC Data Lost.

FIELD SERVICE MODE

Whenever the diagnostic test terminal is earthed with the engine running, the system will enter the Field Service

mode. While in the Field Service Mode the Technician can perform diagnostic testing with out setting new DTCs.

PCM LEARNING ABILITY

The PCM has a "lear ning" ability which allows the PCM to make c orr ec tions f or minor variations in the engine or the

transmission system to improve driveability.

TRANSMISSION ADAPT FUNCTION

The HYDRA-MATIC 4L60-E uses a feedback line pressure control system which has the ability to adapt the

system's line pr essur e to com pensate f or nor m al wear of the clutc h plates, seals , springs , etc. T his learning f eature

is similar to what is used for engine fuel control, short term fuel correction, and long term fuel trim.

The HYDRA-MATIC 4L60-E transmission only uses the adapt function for the 1-2 up-shift. The PCM monitors the

engine speed to determine if the shift is occurring too fast (harsh) or too slow (soft). The PCM will adjust the

pressure control solenoid to m aintain the correct shift feel. The line pressure can adapt to values ranging from 35

kPa below, to 70 kPa above normal line pressure.

Whenever the battery is disconnected, the "learning" process resets. A change may be noted in the vehicle's

perfor m ance. T o teac h the vehicle, reset the IAC valve and ens ure that the engine is at oper ating tem perature. T he

vehicle should be driven at part throttle, with moderate acceleration and idle conditions until normal performance

returns.

Diagnostic tables c ontain diagnosis procedures using a Tech 2 s can tool whenever possible. The T ech 2 sc an tool

contains information about what is happening in the engine/transmission management system.

POWERTRAIN OBD SYSTEM CHECK: EXAMPLE

Step Action Value(s) Yes No

1 Ignition ON engine OFF.

Does the Check Powertrain Lam p (CPL) illuminate

for at least two seconds?

Go to Step 2 Go to Section

12C in VX

Service

Information for

CPL Diagnosis

2 1. Connect a Tech 2 scan tool to the Data Link

Connector (DLC).

2. Turn ON the ignition leaving the engine OFF.

Does the Tech 2 scan tool display Engine ID

Information?

Go to Step 3 Go to Data Link

Connector

Diagnosis

Table in This

Section

3 1. Ignition ON, engine OFF.

2. Using the Tech 2 scan tool, are any PCM

DTC(s) displayed?

Go to the

applicable DTC

table

Go to Step 4

4 1. Ignition ON and wait for a minimum of five

seconds.

2. Turn the key to the crank position.

Does the engine crank?

Go to Step 5 Go to Starter

Cranking

Circuit Table in

This Section

5 Does the engine start and continue to run? Go to Step 6 Go to Engine

Cranks But

Does Not Run

Table in this

Section

6 Compare the Tech 2 scan tool data with the values

shown in the Engine Scan Data Engine Stream.

Are the values normal or within typical ranges?

Go to Step 7 GO TO

DIAGNOSTIC

AIDS AND

TEST

DESCRIPTION

7 1. Check and record, then clear all DTC(s) from

PCM, BCM, and PIM.

2. Retest vehicle.

NOTE:

Insure that the vehicle has been road tested long

enough to meet the customers complaint, or for all

control module system diagnostics to have run.

3. Using the Tech 2 scan tool, re-test for any

reoccurring

DTC(s).

Did any DTC(s) reset?

System OK Go to Step 1

POWERTRAIN OBD SYSTEM CHECK

After the vis ual and physical underhood inspec tion, the POW ERTRAIN OBD SYSTEM CHECK is the starting point

for all diagnostic procedures or finding the cause of an emissions test failure.

All diagnostic procedures must always begin with the POWERTRAIN OBD SYSTEM CHECK.

Diagnostic procedures mus t begin with the PO W ERT RAIN OBD SYSTEM CHECK, which represents an organised

approach for identifying system problems.

The PO WERT RAIN O BD SYSTEM CHECK mak es an initial c heck of the s ystem and dir ec ts the tec hnic ian to other

tables in this Sec tion. It mus t be us ed as a s tar ting point f or all proc edur es. The entire Sec tion is s et up in a s pecif ic

order. The POWERTRAIN OBD SYSTEM CHECK will lead the technician to other tables, and those tables may

lead to still other tables. THE SEQUENCE MUST BE FOLLOWED. The engine/transmission control system uses

many input signals and controls many output functions. If the correct diagnostic sequence is not followed, incorrect

diagnosis and replacement of serviceable parts may occur.

Diagnostic tables incorporate diagnos is proc edures us ing a T ech 2 sc an tool where possible. T his T ech 2 s can tool

is a sm all hand-held computer in its elf. Its function is to give inf orm ation to a technician about what is happening in

the powertrain management system.

The Data Link Connector (DLC) is used by the assem bly plant to perform end of line tes ts. T his c onnector c an also

be used by technician to m onitor certain inputs and outputs as seen by the Powertrain Control Module (PCM). T he

Tech 2 scan tool reads and displays the information (serial data) supplied to the data link connector from the

Powertrain Control Module (PCM).

The correct procedure to diagnose a problem is to follow three basic steps.

1. Are the On-Board Diagnostics working?: This is determined by performing the Powertrain OBD System

Check. Since this is the starting point for the diagnostic procedures or finding the cause of a failure, always

begin here.

If the On- Board Diagnostics ar en't working, the Powertrain O BD System Check will lead to a diagnostic table in

this section to correct the problem. If the On-Board Diagnostics are working correctly, the next step is:

2. Is there a Diagnostic Trouble Code stored?: If a diagnostic trouble code is stored, go directly to the

numbered diagnostic trouble code table in this Section. This will determine if the fault is still present. If no

diagnostic trouble code is stored, then:

3. Observe Serial Data transmitted by the PCM: This involves reading the information available on the Serial

Data Stream with a Tech 2 scan tool. Information on this tool and the meaning of the various displays can be

found in the suc ceeding paragraphs. T ypical data readings under a par ticular operating condition can be found

on the TECH 2 SCAN TOOL DATA pages.

DLC TECH 2 SCAN TOOL

The PCM can communicate a variety of information through DLC connector. This data is transmitted at a high

frequency which requires a Tech 2 scan tool for interpretation.

TECH 2 SCAN TOOL EXPLANATION

To ex plain how the Te ch 2 scan tool works , let's think f or a minute about how a television works. A television is an

electronic device that receives and processes information, and sends out information in a form that can be

understood by the person watching it. The television receives a signal (from a transmitting station) that is not

usable to the person.

The television processes it, then sends the signal to a screen. The person can then see the information that the

television transmitting station sent out. The Tech 2 scan tool is like the television because it also processes

information, sent to it by the PCM.

The information is sent out of the PCM to the Data Link Connector (DLC) serial data line. The Tech 2 scan tool

plugs into the data link connector, and the information is sent to the tool on its cable. The Tech 2 scan tool

processes the information, and "sends" the signal to a display screen on the tool.

Just like a television, you can select which "station" that you want to see. The difference is instead of seeing the

picture on a television, you "see" the display screen, and the "stations" that you can select on a Tech 2 scan tool

are the different input and output signals that are being processed by the PCM.

The Tech 2 scan tool for the GEN III V8 engine has the ability to send messages back to the PCM to do different

things s uc h as s witch outputs O FF and ON . T his allows the tec hnician to c ontr ol the PCM. T his c ontrol only lasts as

long as the Tech 2 scan tool is connected.

TECH 2 SCAN TOOL USES - POWERTRAIN CONTROL MODULE (PCM)

The T ech 2 scan tool is a us eful and quick way of com paring operating parameters of a poorly operating engine or

transmission with a known good one. For example, a s ens or may shift its value but not s et a DT C. Compar ison with

a known good vehicle may uncover this problem.

The T ech 2 scan tool allows a quick check of sensors and switches which are inputs to the PCM. The PCM in the

vehicle sends out inf orm ation to the T ech 2 s can tool at a very fast rate ( Class II serial data), and the display on the

tool can update quicker than a digital multimeter. The Tech 2 scan tool allows a technician to manipulate wiring

harnesses or components under the vehicle while observing the T ech 2 s can tool readout. T his c an help in locating

intermittent connections.

After you enter the proper vehicle information, the first display on the Tech 2 scan tool will ask for what type of

system to select from.

The following is a list of systems the Tech 2 will display:

F0: ENGINE

F1: TRANSMISSION

F3: CHASSIS

F4: BODY

After selecting F0: ENGINE, the scan tool will display:

V6 Supercharge

V8 GEN III

V6 LPG

DTC CHECK

Other

Once the correct engine has been selected, the Tech 2 scan tool will now have five test modes for diagnosis and

service of the PCM system. The five test modes are as follows:

• MODE F0: DIAGNOSTIC TROUBLE CODES

In this test mode, DTCs stored by the PCM maybe displayed or cleared. When entering this mode there are four

modes:

F0. READ DTC INFO ORDERED BY PRIORITY:

DTC will be displayed in the order of priority.

F1. CLEAR DTC INFORMATION: Clears all DTC(s) in the vehicle’s PCM memory. Also clears Freeze

Frame/Failure Records, so before clearing codes, be sure to retrieve Freeze Frame / Failure Records.

F2. DTC INF ORMATION: Shows codes which are s et that match the criter ia. Each code has its own page of

information. If multiple codes are set, the user must page through the display of codes:

F0: HISTORY: This DTC search will display only DTCs that are stored in the PCM memory as Valid Faults,

but are currently not active.

F1: Check Powertrain Lamp (CPL) MESSAGE REQUESTED: This DTC search will display only DTCs

that are requesting the Check Powertrain Lamp/CPL to turn ON.

F2: LAST TEST FAILED: This DTC search will display only DTCs that failed the last time the test ran.

F3: TEST FAILED SINCE CODE CLEARED: T his DT C search will display all DTCs that have reported a

test failure since the last time DTCs were cleared.

F4: NO T RAN SINCE CODE CLEARED: T his DT C s earch will display only DTCs that have not r an since

DTCs were last cleared. Any displayed DTCs have not run, therefore their condition (passing or

failing) is unknown.

F5: FAILED T HIS IGNITIO N: This DT C search will display all DTCs that have f ailed at least once during

the current ignition cy cle.

F3: FREEZE FRAME / FAILURE RECORDS: Shows Freeze Frame / Failure Records information. Freeze

Frame / Failure Records are types of snapshots in the memory of the vehicle’s controller.

• MODE F1: DATA DISPLAY

This mode displays data parameters for the controller being diagnosed. When entering this mode, there are two

modes:

F0: ENGINE DATA: In this test mode, the Tech 2 scan tool continuously monitors system data, such as

engine speed data, engine coolant temperature etc.

F1: FUEL TRIM DATA: In this test m ode, the Tech 2 scan tool continuously monitors system data, such as

engine speed data, engine coolant temperature, HO2S, Fuel Trim Cell etc.

• MODE F2: SNAPSHOT

In this test m ode, the Tec h 2 scan tool captur es data before and after a snapshot triggering condition which may or

may not set a DTC.

• MODE F3: MISC. TESTS

In this test mode, the Tech 2 scan tool performs software override commands of the PCM, to assist in problem

isolation during diagnostics:

F0: OUTPUT TESTS

F0: FUEL PUMP

F1: A/C CLUTCH

F2: Check Powertrain Lamp (CPL)

F3: HIGH FAN

F4: CANISTER PURGE

F1: IAC SYSTEM

F0: RPM CONTROL: Used to control engine RPM from 600 RPM to 1675 RPM.

F1: IAC CONTROL: Used to control IAC steps from 0 to 120.

F2: IAC RESET: Used to reset IAC if the IAC is lost or if IAC has been replaced.

F3: BASE IDLE: Used to set the engine to base idle.

F2: RESET CELLS

Resets all LT Fuel Trim values to 0%

F3: 02 LOOP STATUS

With the engine running, Open or Closed Loop fuel control can be commanded.

With the engine running, forces air fuel ratio from 11.7 to 17.7.

• MODE F4: FUNCTIONS TESTS

This mode performs functional tests on the PCM system which help verify proper operation. In this mode, fault

conditions are automatically logged by the Tech 2 scan tool.

The Tech 2 scan tool also has the ability to send commands to the PCM, instructing the PCM to perform various

functions or tasks. This provides a quick way to determine if a device is operational or not. In the F4 mode, the

following tests can be performed:

F0: IAC CIRCUIT: Designed to c onfirm IAC motor f unctions OK and is not losing track of position. Monitors the

engine speed. Repeatedly cycles the IAC m otor in and out and then m onitors the engine speed. If OK, turn

ignition OFF and start repeatedly, then stabilise idle. If the value of final idle RPM is greater than a

calibrated threshold, then the IAC circuit has failed.

F1: PW R (POW ER) BALANCE: Designed to identify low power output from individual cylinders. Automatically

cycles each injector OFF and ON while monitoring and recording the RPM drop for each cylinder.

F3: WRNG (WIRING) HARNESS: Designed to confirm no intermittent open or short circuits exist in selected

circuits . Engine is at idle in N. T echnician s hould wiggle powertrain harness. T he Tec h 2 scan tool monitors

inputs that should rem ain relatively static at idle such as: ECT , IAT, TP Sensor, VSS, CAM signal present,

18X signal present, EST lines, injector voltage m onitor, battery, ignition. If discontinuity occurs, the T ech 2

scan tool logs DTC and prompts technician to check the appropriate circuit.

F2: FUEL INJECT OR BALANCE: Des igned to check f unction of each injec tor while the engine is not running. A

fuel pres sure gauge has to be connec ted to the fuel rail and pres sure drop has to be recorded after turning

ON each injector.

TECH 2 SCAN TOOL USES - POWERTRAIN INTERFA CE MODULE (PIM)

The PIM in the vehic le sends out infor m ation to the T ech 2 scan tool at a ver y fast rate (UART ser ial data), and the

display on the tool can update quicker than a digital multimeter. The Tech 2 scan tool allows a technician to

manipulate wiring harnesses or components under the vehicle while observing the Tech 2 scan tool readout. This

can help in locating intermittent connections.

After you enter the proper vehicle information, the first display on the Tech 2 will ask for what type of system to

select from.

The following is a list of systems the Tech 2 will display:

F0: ENGINE

F1: TRANSMISSION

F2: CHASSIS

F3: BODY

After selecting F3: BODY, the scan tool will display:

Body Control Module

Powertrain Interface Module

SRS

Instrument

Electronic Climate Control

DTC Check

Other

Once the PIM has been selected, the T ech 2 scan tool will now have five test modes for diagnosis and service of

the PIM system.

The five test modes are as follows:

• MODE F0: PIM NORMAL MODE

In this test mode, the scan tool monitors data sent from the PIM to other vehicle system control modules on the

serial data line. This data represents the normal bus communication executed during ignition ON. The PIM keeps

the other control modules that are connected on the serial data line informed about the status of the PCM

parameters. These parameters are collected from the PIM via serial data communication with the PCM.

The Engine Check Powertrain Lamp (CPL) in the instrument cluster is driven only with this status report in the

PIM's Normal Mode bus message. If PCM Check Powertrain Lamp (CPL) status report indicates OFF, the Check

Powertrain CPL on the instrument panel should be OFF.

The f ollowing PIM Norm al Mode controller us age table, indicates specif ic Control Modules using the PCM supplied

report status information:

PIM NORMAL MODE CONTROLLER USAGE TABLE

PIM NORMAL MODE

SCAN TOOL

PARAMETERS

USED BY:

Scan Tool S tring BCM INST E CC ABS/

ETC

Engine Speed √

√√

√

Coolant Tem perature √

√√

√

Barometric Pressure *

Vehicl e S peed √

√√

√

A/C Clutch

A/C Pressure √

√√

√

Low Speed Fan Request √

√√

√

Low Fan Run ON √

√√

√

Theft St atus √

√√

√

PCM DTC Status √

√√

√

Check P owertrain CPL √

√√

√

Throttle Failure * √

√√

√

MAP Failure *

Fuel Used √

√√

√

Fuel Flow Rate √

√√

√

Engine Type √

√√

√

Transmission Coding

Fuel Type √

√√

√

Engine Oil Change √

√√

√

Scan Tool S tring BCM INST E CC ABS/

ETC

Transm i ssion Oil Change √

√√

√

Shift Pattern √

√√

√

Throttle Position * √

√√

√

Torque Multiplier √

√√

√

High Coolant Temperature

Low Coolant Level * √

√√

√

Oil Pressure Sensor √

√√

√

PRNDL Switch √

√√

√

Commanded Gear √

√√

√

PCM Chime √

√√

√

* Indicates Only With GEN III V8 Engine

• MODE F1: DIAGNOSTIC TROUBLE CODES

In this test mode, DTCs stored by the PCM maybe displayed or cleared. When entering this mode there are two

modes:

F0. READ CURRENT DTC INFORMATION: DTCs will be displayed in the PIM by priority or in sequence.

F1. CLEAR DTC INFORMATION: The scan tool will clear all stored DTCs from the PIM memory.

• MODE F2: DATA DISPLAY

In this test mode, the Tech 2 scan tool continuously monitors system data, such as: starter relay, password

learning, engine oil change etc.

• MODE F3: SNAPSHOT

In this test m ode, the Tec h 2 scan tool captur es data before and after a snapshot triggering condition which may or

may not set a DTC.

• MODE F4: MISC. TESTS

In this test mode, the Tech 2 scan tool performs software override commands of the PIM, to assist in problem

isolation during diagnostics.

F0: OUTPUT TESTS

F0: STARTER RELAY

TECH 2 SCAN TOOL USE WITH INTERMITTENT FAULTS

The T ech 2 scan tool allows m anipulation of wiring harnesses or c omponents under the bonnet with the engine not

running, while observing the Tech 2 scan tool readout.

The T ech 2 s can tool can be plugged in and obs erved while driving the vehicle under the condition when the Check

Powertrain Lamp (CPL) turns ON momentarily or engine driveability is momentarily poor. If the problem seems to

be related to certain par am eters that c an be check ed on the Tec h 2 scan tool, they should be check ed while driving

the vehicle. If there does not seem to be any connection between the problem and any specific circuit, the T ech 2

scan tool can be used to m onitor eac h parameter , watching for a period of time to s ee if there is any change in the

readings that indicates an intermittent condition.

The Tech 2 scan tool can capture and store data when the problem occurs, so it can be played back at a slower

rate to determine what happened to the system. This is called the SNAPSHOT mode.

The Tech 2 scan tool is an easy way to com pare the operating param eters of a poorly operating engine with those

of a known good one. For example, a sensor may shift in value but not set a DTC. Comparing the sensor's

readings with those of a known good vehicle may uncover the problem.

The Tech 2 s c an tool saves time in diagnos is and helps to pr event the r eplacement of s er viceable par ts. The k ey to

using the Tech 2 scan tool successfully is the technician's ability to understand the system being diagnosed, as

well as understanding the Tech 2 scan tool operation and its limitations. The technician should read the Tech 2

operator’s manual to become familiar with the Tech 2 scan tool operation.

With an understanding of the data which the tool displays, and knowledge of the circuits involved, the tool can be

very useful in obtaining information which would be more difficult or impossible to obtain with other equipment.

The T ech 2 scan tool does not make the use of diagnostic tables unnecessary, nor can it indicate exactly where a

problem is in a particular circuit. Diagnostic Tables inc orporate diagnosis pr ocedures that require the use of a Tec h

2 scan tool.

TECH 2 SCAN TOOL LIMITATIONS

The Tec h 2 sc an tool m ust receive the s ignal f rom the PCM in or der to display any useable infor m ation. If the PCM

sends no signals to the data link connec tor, or the connec tion to the Tech 2 sc an tool is defec tive, the Tech 2 scan

tool will only display, WAITING FOR DATA - NO DATA RECEIVED FROM PCM. The Powertrain OBD System

Check instructs the technician what to do if this happens.

The T ech 2 sc an tool has a few lim itations. If the T ech 2 sc an tool is displaying a PCM "output" function, it displays

only the comm and given by the PCM. That does not mean that the des ired action took place. T his is sim ilar to the

automatic transmission dashboard gearshift indicator. Just because the gearshift P R N D L pointer indicates the

transm ission is in DRIVE does not mean that the trans mission is actually in that gear. To be s ure, you mus t check

the linkage and adjustment at the transmission.

When using the T ech 2 s c an tool to obs erve one of the PCM "output" functions , suc h as an idle air c ontr ol m otor, or

a TCC s olenoid, the technician must not assume the indic ated is the same as the actual. If the Tech 2 scan tool is

displaying TCC s olenoid as being ON , but the wire to power it is dis connec ted or def ec tive, the PCM in some c as es

has no way of knowing it. The display may indicate the command is ON, but the device may not be operating!

The Tech 2 s c an tool saves time in diagnos is and helps to pr event the r eplacement of s er viceable par ts. The k ey to

using the Tech 2 scan tool successfully for diagnosis is the technician's ability to understand the system being

diagnosed, as well as an understanding of the Tech 2 scan tool's limitations.

With an understanding of the data the Tec h 2 scan tool dis plays, and knowledge of the circuits involved, the Tec h 2

scan tool is useful in obtaining information which is difficult or impossible to retrieve with other methods.

Remem ber, the Tech 2 scan tool does NOT make using diagnostic tables unnecessary, nor can it tell you exactly

where a problem is in a circuit. Most diagnostic tables incorporate diagnosis procedures that require the use of a

Tech 2 scan tool.

TECH 2 SCAN TOOL: PI M NORMAL MODE

The Tech 2 scan Tool PIM Normal Mode in the table may be used for comparison if a status report is being sent

from the PIM.

1. After completing the Powertrain OBD System Check

2. Finding the on-board diagnostics are functioning properly and

3. No diagnostic DTCs are displayed.

The asterisk applies only to the GEN III V8 engine application.

A TECH 2 SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM

SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY TECH 2 SCAN TOOL CAN

RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT. Only the parameters listed are

used of the VT Series II Servic e Infor mation for diagnosis. For m ore desc ription on the values and use of the Tec h

2 scan tool to diagnosis PCM/PIM inputs, refer to the applicable diagnosis table in this Section. If all values are

within the range illustrated, refer to SYMPTOMS Tables in Section 6C3-2B of the VT Series II Service Information.

Test Description: The number(s) below refer to the number(s) on the Tech 2 Scan Data Engine Stream table.

1. The Tech 2 s can tool FO: PCM/PIM NORMAL MO DE will display scan positions that will be displayed in order.

The Tech 2 sc an tool will dis play nine (9) scan pos ition param eters at a tim e. The down arrow button will scr oll

down through all of the scan positions one at a time. After TIME FROM START parameter is displayed,

pressing the down arrow button again, will display scan position parameters starting at the top of the list again.

2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a

value that is being sensed or being issued by the PCM.

3. TYPICAL DATA VALUE is separated into two parts. T hese displayed values are typical of a normally operating

vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a

failure. The ENGINE RUNNING data should be compared to the IGNITION ON data as a diagnostic check to

make sure the component or system is operating properly.

4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON

and engine stopped. Temperature sensors should be compared to the actual temperatures by allowing the

sensor to cool overnight and then comparing their values. A difference of 3-5° C from the actual temperature

may indicate a problem with the s ens or. Us e the diagnos tic aids table f or that s ensor to c ompare the r esis tanc e

to temperature values.

4. ENGINE RUNNING typical data values are an average of display values recorded from normally operating

vehicles at norm ally operating tem perature. T hey are intended to repr esent what a normally functioning system

would typically display.

TECH 2 SCAN TOOL: PIM Normal Mode

TYPI CAL D ATA VALUE !

SCAN POSITION " UNITS DISPLAYED # IGNITION ON $ ENGINE RUNNING %

ENGINE S PEED RPM 0 RPM 600 - 650 RPM

(± 50 RPM IN DRIVE )

COOLANT TEMPERATURE DEGREES C Varies +96 C

BAROMETRIC PRESSURE

kPa 0 to 200 kPa

(VARIES) 0 to 200 kPa

(VARIES)

VEHICLE SPEED km/h 0 0

A/C CLUTCH ON /OFF OFF OFF

A/C PRESSURE kPa 896 kPa 800 - 1000 kPa A/ C OFF

1600 - 1900 kPa A/C ON

LOW SPEED FAN REQUEST ON / OFF OFF OFF

LOW FAN RUN ON YES / NO NO NO

THEFT STATUS (only BCM-PIM) NO START / START START START

PCM DTC STA T US NO DTC(s)/DT C(s)

SET NO DTC(s) NO DTC(s)

CHECK POWERTRAIN

LAMP (CPL) OFF/ON ON OFF

THROTTLE FAILURE YES/ NO NO NO

MAP FAILU R E YES/NO NO NO

FUEL USED L 00.00 1 - 2 L/ Hour

FUEL FLOW RATE 00.00 1 - 2 L/ Hour

ENGINE TYPE V6, V8,

V6 SUPERCHARGE,

V8 GEN 3

V8 GEN 3 V8 GEN 3

TRANSMISSION CODING MANUAL TRANS.

AUTO TRANS. MANUAL TRANS.

AUTO TRANS.

FUEL TYPE PETROL / LPG PETROL PETROL

ENGINE OI L CHA NGE OKAY /

SERVICE REQUIRED OKAY OKAY

TRANSMISSION OIL CHANGE OKAY /

SERVICE REQUIRED OKAY OKAY

SHIFT PATTERN ECONOMY/POWER ECONOMY ECONOMY

THROTTLE POSITION 0-100 % 0% 0%

HIGH COOLANT TEMPERA TURE YES/NO NO NO

LOW COOLANT LEVEL YES/NO NO NO

OIL PRESSURE SENSOR OFF/ON OFF OFF

PRNDL SWITCH INVALID /

P,R,N,D,3,2,1 INVALID

GEAR SELECTED

INVALID

GEAR SELECTED

COMMANDED GEAR P/N R, 1 P/ N P/N

PCM CHIME YES/NO YES YES

TECH 2 SCAN TOOL: PI M NORMAL MODE DESCRIPTIONS

A list of ex planations for each data me ssage displayed on the Tech 2 s can tool is listed below. This information will

assist in diagnosing em iss ion or driveability problems . T he displays can be viewed while the vehicle is being driven.

Refer to the Powertrain OBD Sy stem Check for additional information.

ENGINE SPEED: Tech 2 Displays a range of 0 to 9999 RPM

The engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired

idle speed under various engine loads with engine idling.

COOLANT TEMPERATURE: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)

The Engine Coolant Temperature (ECT) sensor is mounted in the cylinder head of the left bank. The PCM apples

5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature

changes. W hen the sensor is cold (internal r esistance high), the PCM m onitors a high s ignal voltage and interprets

the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases

and the PCM interprets the lower voltage as a warm engine.

BAROMETRIC PRESSURE (BARO) SENSOR: Tech 2 Displays a range of 0 to 200 kPa / 0 to 5.0 volts

The BARO reading is displayed in volts and kPa and represents the altitude of the vehicle for the transmission

control. At sea level the BARO reading is about 4.7 to 4.9 volts. At 3048 m eters (10,000 feet) the BARO reading is

about 2.5 to 3.0 volts.

* ( Only with GEN III V8 Engine)

VEHICLE SPEED: Tech 2 Displays a range of 0 to 255 km/h

The vehicle speed sensor signal is converted into km/h and mph for display.

A/C CLUTCH: Tech 2 Displays "ON" or "OFF"

Represents the commanded state of the A/C clutch control relay. Clutch should be engaged when ON is displayed.

A/C PRESSURE: Tech 2 Displays a range of 0 to 3195 kPa

The kPa displayed indicates that the PCM is monitoring an A/C Refrigerant Pressure signal voltage which is too

high or too low to allow the A/C compressor clutch to engage.

LOW SPEED FAN REQUEST: Tech 2 Displays "ON" or "OFF

Indicates if the engine cooling fan low speed relay has been commanded ON or OFF.

LOW FAN RUN ON: Tech 2 Displays "NO" or "YES"

This indicates if the PCM is requesting the BCM to turn the Low Speed Fan ON at key OFF.

THEFT STATUS: Tech 2 Displays "NO START" or "START"

Indicates the status of the Theft Deterrent System.

PCM DTC STATUS: Tech 2 Displays "NO DTC(s)" or “DTC SET”

Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC are or are not set.

CHECK POWERTRAIN LAMP (CPL) or MALFUNCTION INDICATOR LAMP (MIL): Tech 2 Displays "OFF" or

"ON"

Indicated if the instrument panel Malfunction Indicator Lamp is ON or OFF.

THROTTLE FAILURE: Tech 2 Displays "NO" or "YES"

Indicates if the throttle position sensor has failed. This is reported from the PCM to the PIM.

* (Only with GEN III V8 Engine)

MAP FAILURE: Tech 2 Displays "NO" or "YES"

Indicates if the Map sensor has failed. This is reported from the PCM to the PIM.

* (Only with GEN III V8 Engine)

FUEL USED: Tech 2 Displays a range of 0 to 1000 Litres

When the key is turned ON and the engine is running, the PCM will calculate FUEL USED during each ignition

cycle.

FUEL FLOW RATE: Tech 2 Displays a range of 0 to 100 litres

Indicates fuel consumption per litres per hour.

ENGINE TYPE: Tech 2 Displays Engine Type

The Tech 2 uses this information for proper Tech 2 scan tool software.

TRANSMISSION CODING: Tech 2 Displays “MANUAL” or “AUTOMATIC”

The Tech 2 uses this information for proper Tech 2 scan tool software

FUEL TYPE: Tech 2 Displays “PETROL” or “LPG”

The scan tool will display what fuel type the PCM software is set up for.

ENGINE OIL CHANGE: The Tech 2 Displays “OKAY” or “SERVICE REQUESTED”

The scan tool will display the status of the engine oil change condition.

TRANSMISSION OIL CHANGE: The Tech 2 Displays “OKAY” or “SERVICE REQUESTED”

The scan tool will display the status of the transmission oil change condition.

SHIFT PATTERN: Tech 2 Displays “ECONOMY” or “POWER”

This display shows the state of the ECONOMY/POWER switch.

THROTTLE POSITION: Tech 2 Displays a range of 0 to 100%

Computed by the PCM from TP sens or voltage (Throttle Position) should read 0% at idle and 100% at W ide Open

Throttle (WOT).

* (Only with GEN III V8 Engine)

HIGH COOLANT TEMPERATURE: Tech 2 Displays "NO" or "YES"

This is an indication to the PCM that the engine is running hot.

LOW COOLANT LEVEL: Tech 2 Displays "NO" or "YES"

This is an indication to the PCM that the coolant level is low, and the PCM will turn on the Low Coolant lamp.

* (Only with GEN III V8 Engine)

OIL PRESSURE SENSOR: Tech 2 Displays "OFF" or "ON"

This is an indication to the PCM if the oil pressure is high or low. If the oil pressure is low, the PCM will turn on a

Low Oil Warning Lamp.

PRNDL SWITCH: Tech 2 Displays “INVALID” or “P, R, N, D, 3, 2, 1”

This displays if the vehicle is not equipped with a PRNDL switch (INVALID), or if equipped, indicates what gear the

driver has selected.

COMMANDED GEAR: Tech 2 Displays “1, 2, 3, 4”

The gear that the PCM is c om m anding the transmis sion to be in. In PARK, the T ech 2 sc an tool will display "1", the

commanded state of the shift.

PCM CHIME: Tech 2 Displays "NO" or "YES"

This is a indication to the instrument panel allowing the instrument panel to chime if a problem or fault is detected.

TECH 2 SCAN TOOL: ENGINE DATA

The Tech 2 scan Data listed in the table may be used for comparison

1. After completing the Powertrain OBD System Check

2. Finding the on-board diagnostics are functioning properly and

3. No diagnostic DTCs are displayed.

A TECH 2 SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM

SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY TECH 2 SCAN TOOL CAN

RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.

Only the param eters listed are used of the VT Series II Service Information for diagnosis. For more description on

the values and use of the Tech 2 scan tool to diagnosis PCM inputs, refer to the applicable diagnosis table in this

Section. If all values are within the range illustrated, refer to SYMPTOMS Tables in Section 6C3-2B of the VT

Series II Service Information.

Test Description: The number(s) below refer to the number(s) on the Tech 2 Scan Data Engine Stream table.

1. The Tech 2 scan tool F2: DATA LIST will display scan positions that will be displayed in order. The Tech 2

scan tool will display nine (9) scan position parameters at a time. The down arrow button will scroll down

through all of the s can positions one at a tim e. After TIME F ROM START parameter is displayed, pressing the

down arrow button again, will display scan position parameters starting at the top of the list again.

2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a

value that is being sensed or being issued by the PCM.

3. TYPICAL DATA VALUE is separated into two parts. T hese displayed values are typical of a normally operating

vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a

failure. The ENGINE RUNNING data should be compared to the IGNITION ON data as a diagnostic check to

make sure the component or system is operating properly.

4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON,

and engine stopped. Temperature sensors should be compared to the actual temperatures by letting the

sensor stabilise overnight and then com paring their values. A difference of 3-5° C from the actual temperature

may indicate a problem with the s ens or. Us e the diagnos tic aids table f or that s ensor to c ompare the r esis tanc e

to temperature values.

5. ENGINE RUNNING typical data values are an average of display values recorded from normally operating

vehicles at norm ally operating tem perature. T hey ar e intended to represent what a norm ally func tioning system

would typically display.

TECH 2 SCAN TOOL: ENGINE DATA

TYPICAL DATA VALUE !

SCAN POSITION " UNITS DISPLAYED #

IGNITION ON $ ENGINE RUNNING %

ENGINE SPEED RPM 0 RPM ± 100 RPM FROM DESIRE D RP M

(± 50 RPM IN DRIVE)

DESIRED IDLE SPEE D RPM 0 RPM PCM IDLE COMMAND (VARIES WITH

TEMPERATURE)

ENG. COOLANT TEMP (E CT) DEGREES C VARIES +96° C

START UP ECT DEGREES C VARIES VARIES

IAT DEGREES C VARIES VARIES

MAP SENSOR kPa VARIES VARIES

MAP SENS OR V OLTS VOLTS 4.6 Volts 1 to 2 Volts

MASS AI R FLOW GRAM /SEC 0 g/s 5 -10 g/s

MAF SENSOR FREQUENCY Hz 0 Hz 2200-2500 Hz

BARO kPa VARIES VARIES

BARO SENS OR V OLTS VOLTS 4.6 VOLTS 4.5 VOLTS

THROTTLE POSI TI ON 0-100 % 0 % 0 %

THROTTLE POSI TI ON SENSOR VOLTS 0.32 V 0.47 V

FUEL SYSTEM STATUS OPEN LOOP/

CLOSED LOOP OPEN LOOP CLOSED LOOP

INJECTION PULSE B ANK 1 mS 0.00 mS 3.00 - 3.50 mS

INJECTION PULSE B ANK 2 mS 0.00 mS 3.00 - 3.50 mS

AIR FUEL RA TI O % 0.01 14.7:1

SPARK ADVANCE DEGREES 0°BTDC 13° BTDC

IGNITION COIL CYL. 1 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 2 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 3 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 4 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 5 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 6 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 7 OKAY / FAULT OKAY OKAY

IGNITION COIL CYL. 8 OKAY / FAULT OKAY OKAY

KNOCK PRESENT YES / NO NO NO

KNOCK RETARD DEGREES 0° 0°

CAMSHAFT ACTIVITY COUNTS 0 INCRUMENTING FROM 0 UP T O 65535

PURGE PWM % 0% 17%

HIGH SPEED FAN OFF / ON OFF OFF

A/C REQUEST YES / NO NO NO

A/C CLUTCH ON / OFF OFF OFF

A/C PRE SSURE kPa 1151 k P a 1091 kPa

REVERS E LOCK -OUT SOL ON/OFF ON ON

TRANSMISSION RANGE PARK, REVERSE,

NEUTRAL, DRIVE 4

OD, DRIVE 3 / D,

DRIVE 2, DRIVE 1,

INVALID

PARK PARK

COMMANDED GEAR 1,2,3,4 1 1

TCC SOLENOID ON / OFF OFF OFF

TCC PWM SOLE NOI D % 0% 0%

TCC BRAKE SWITCH ON / OFF OFF OFF

ENGINE OI L PRESSURE PSI 39 PSI 200 - 225 PSI

ENGINE OIL PRESSURE VOLTS 0.7 VOLTS 1.5 VOLTS

THEFT STATUS NO START / START START START

ENG. COOLANT LEVEL SWITCH ON / OFF OFF OFF

IDLE AI R CONTROL STEPS 169 52

DESIRE D IAC AI RFLOW 0-64 g/s 9.4 g/s 5. 8 g/s

VEHICLE SPEED km/h 0 0

BATTERY VOLTAGE vol t s 12 14

DTC STA T US NO DTC / DTCs SET NO DTC NO DTC

TIME FROM START TIME 0:00:00 VARIES

TECH 2 SCAN TOOL: ENGINE DATA DESCRIPTIONS

A list of ex planations for each data me ssage displayed on the Tech 2 s can tool is listed below. This information will

assist in diagnosing em iss ion or driveability problems . T he displays can be viewed while the vehicle is being driven.

Refer to the Powertrain OBD Sy stem Check for additional information.

ENGINE SPEED: Tech 2 Displays a range of 0 to 9999 RPM

The engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired

idle under various engine loads with engine idling.

DESIRED IDLE SPEED: Tech 2 Displays a range of 0 to 3175 RPM

The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the

engine at the desired idle speed.

ENGINE COOLANT TEMPERATURE: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)

The Engine Coolant Temperature (ECT) sensor is mounted in the cylinder head of the left bank. The PCM apples

5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature

changes. W hen the sensor is cold (internal r esistance high), the PCM m onitors a high s ignal voltage and interprets

the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases

and the PCM interprets the lower voltage as a warm engine.

START UP ECT: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)

The scan tool displays the Engine Coolant Temperature at the time the engine was started. The PCM uses

Start Up ECT for certain DTCs.

IAT: Tech 2 Displays a range of -39°C to 104°C (-38°F to 284°F)

The PCM converts the resistance of the Intake Air Temperature sensor to degrees. The PCM uses the Intake Air

Temperature (IAT) in order to adjust fuel delivery and spark timing according to incoming air density.

MAP: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.0 volts

The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from engine

load, and speed changes. As the intake manifold pressure increases, the intake vacuum decreases resulting in a

higher MAP sensor voltage and kPa reading. The PCM uses the MAP s ensor signal for the f ollowing: (1) Updating

the BARO reading; (2) Enabling factor for several of the diagnostics.

MASS AIR FLOW: Tech 2 Displays a range of 0 to 246 Grams/Sec

The Mass Air Flow (MAF) sensor measures the change in the intake air flow which results from engine load and

speed changes. As intake air flow increases, the air in the inlet manifold also increases and addition fuel is

required.

MAF: Tech 2 Displays a range of 0 to 10,192 Hz

The signal that is sent from the Mass Air F low ( MAF) sensor to the PCM is in the form of a frequenc y output. This

frequency output changes as the demand of engine air intake changes.

BARO: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.00 Volts

The Barometric Pressure reading is determined from the MAP sensor signal. The PCM monitors the MAP signal

during key up and Wide Open Throttle (WOT) conditions. The Barometric Pressure compensates for altitude

differences.

TPS ANGLE: Tech 2 Displays a range of 0 to 100%

Computed by the PCM from the TP sensor voltage. The TP angle should read 0% at idle to greater than 80% at

Wide Open Throttle.

TPS VOLTAGE: Tech 2 Displays a range of 0 to 5.10 Volts

Used by the PCM to determine the amount of throttle demanded by the driver. The TPS voltage should read

between 0.25 - 1.25 volts at idle to greater than 4 volts at wide open throttle.

FUEL SYSTEM STATUS: Tech 2 Displays “OPEN LOOP” or “CLOSED LOOP”

CLOSED LOOP indicates that the PCM is controlling fuel delivery according to oxygen sensor voltage. In OPEN

LOOP, the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on TP sensor,

engine coolant, and MAF sensor inputs only.

INJECTION PULSE BANK 1 / BANK 2: Tech 2 displays a range of 0 to 100 m/sec

The Inj ector average indicated the am ount of tim e the PCM com mands each injector ON during each engine cycle.

A longer injector pulse with causes more fuel to be delivered. The Injector Pulse Width increases with increased

engine load.

AIR /FUEL RATIO: Tech 2 Displays a range of 0.00 : 99.99

The Air Fuel ratio is determined from the Heated Oxygen sensor output. The PCM uses the fuel trim to adjust

fueling to attempt to maintain an Air Fuel Ratio of 14.7:1. A lower value indicates a richer commanded air fuel

mixture while a higher value indicates a leaner mixture.

SPARK ADVANCE: Tech 2 Displays a range of -64 to 64°

The scan tool displays the amount of degrees the PCM commands the spark advance on the Ignition Control (IC)

circuit. The PCM computes the desired spark advance using the following: (1) Engine coolant temperature; (2)

Engine speed (RPM); (3) Load; (4) Vehicle speed. The PCM adjusts the timing.

IGNITION COIL CYL. 1 through 8: Tech 2 Displays “OKAY” or “FAULT”

This indic ates if there is a f ault in a ignition c oil driver c irc uit. If a fault is pr esent, the Tech 2 will display FAULT, and

a DTC will set.

KNOCK PRESENT: Tech 2 Displays “YES” or “NO”

Indicates whether or not a knock signal is being detected by the PCM. Should read NO at idle.

KNOCK RETARD: Tech 2 Displays a range of 0.0° to 16°

Knock Retard indicates the am ount of s park the PCM rem oves f rom the IC spark advance in response to the signal

from the knock sensor.

CAMSHAFT ACTIVITY: Tech 2 Displays a range of 0 to 65535 counts

The counts increment as the PCM detects the Camshaft sensor signal voltage.

PURGE PWM: Tech 2 Displays a range of 0 to 100%

The PCM commands the PWM duty cycle of the EVAP Purge Solenoid valve. 0% displayed indicates no purge;

100% displayed indicates full purge.

HIGH SPEED FAN: Tech 2 Displays "OFF" or "ON"

Indicates if the engine cooling fan high speed relay has been commanded ON or OFF.

A/C REQUEST: Tech 2 Displays “YES” or “NO”

The A/C Reques t displays the st ate of the A/C reques t input c irc uit f rom the HVAC c ontrols . The PCM uses the A/C

request signal in order to determine whether the A/C compressor operation is being requested.

A/C CLUTCH: Tech 2 Displays “ON” or “OFF”

The A/C Clutch represents the com manded state of the A/C clutch control relay. W hen the scan tool displays ON,

the A/C clutch should be engaged.

A/C PRESSURE: Tech 2 Displays 15 to 452 psi/ 103 to 3116 kPa

This parameter represents the A/C Refrigerant Pressure Transducer signal The amount of pressure indicates the

amount of load that the A/C compres s or plac es on the engine. T he PCM us es this inf ormation in or der to adj us t idle

and in order to control the cooling fans.

REVERSE LOCK-OUT SOL: Tech 2 Displays “ON” or “OFF”

This indicates the status of the manual transmission reverse lock-out solenoid. W hen the scan tool indicates ON,

the transmission can be shifted into reverse gear. W hen the scan tool indicates OFF, the transmission cannot be

shifted into reverse gear.

TRANSMISSION RANGE: T ech 2 Displays “ Park/Neutral - Rev erse - Drive 4 - Driv e 3 - Drive 2 - Drive 1” - or

“Invalid”

Tech 2 displays the transmission gear position.

COMMANDED GEAR: Tech 2 Displays “1-4”

Tech 2 displays which gear the transmission is in. An illegal transmission position displays 9.

TCC SOLENOID: Tech 2 Displays “ON” or “OFF”

Indicates if the TCC enable Solenoid is commanding the TCC ON or OFF.

TCC PWM SOLENOID: Tech 2 Displays “ON” or “OFF”

This parameter is the commanded state of the TCC PWM solenoid. The scan tool displays ON when the

commanded state of the solenoid requests ON. The scan tool displays OFF when the solenoid is not ON.

TCC BRAKE SWITCH: Tech 2 Displays “ON” or “OFF”

This param eter indic ates the state of the T CC brak e switch cir cuit input. T he scan tool dis plays ON when you apply

the vehicle brakes. The torque converter clutch disengages. The scan tool displays OFF when you release the

vehicle brakes. This allows the torque converter clutch to engage.

ENGINE OIL PRESSURE: Tech 2 Displays a range of 0 to 144 psi/0 to 992 kPa/0.0 to 5.0 Volts

The Engine Oil Pressure Sensor measures the engine oil pressure. As the RPM increases from the idle position,

the engine oil pressure will also increase. W hen the oil pressure reaches a predeterm ined low value, the PCM will

turn ON the Low Oil Warning lamp.

THEFT STATUS: Tech 2 Displays "NO START" or "START"

Indicates the status of the Theft Deterrent System.

ENGINE COOLANT LEVEL SWITCH: Tech 2 Displays “OFF” or “ON”

The scan tool will display ON if the coolant level is low. If the coolant level is normal, the scan tool will display OFF.

IDLE AIR CONTROL: Tech 2 Displays a range of 0 to 255 Counts

Displays the commanded position of the Idle Air Control pintle in counts. The higher the number of counts, the

greater the commanded idle speed. The Idle Air Control valve should respond quickly to changes in engine load.

DESIRED IAC AIRFLOW: Tech 2 Displays a range of 0 to 64 Grams Per Second (g/s)

This parameter displays the calculated airflow in the IAC passage.

VEHICLE SPEED: Tech 2 Displays a range of 0 to 255 km/h

The vehicle speed sensor signal is converted into km/h and mph for display.

BATTERY VOLTAGE: Tech 2 Displays a range of 0 to 25.5 volts

This represents the system voltage measured at the PCM.

DTC STATUS: Tech 2 Displays "NO DTC(s)" or “DTC SET”

Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC (s) are or are not set.

TIME FROM START: Tech 2 Displays “0:00:00”

Indicates the hours, minutes and seconds the engine has been running.

TECH 2 SCAN TOOL: FUEL TRIM DATA

The Tech 2 scan Data listed in the table may be used for comparison

1. After completing the Powertrain OBD System Check

2. Finding the on-board diagnostics are functioning properly and

3. No diagnostic DTCs are displayed.

A TECH 2 SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM

SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY TECH 2 SCAN TOOL CAN

RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.

Only the parameters listed are us ed in this m anual f or diagnosis . For m or e descr iption on the values and use of the

Tec h 2 s can tool to diagnos is PCM inputs , r ef er to the applicable diagnos is table in this Sect ion. If all the values ar e

within the range illustrated, refer to SYMPTOMS Tables in Section 6C3-2B of the VT Series II Service Information.

Test Description The numbers below refer to the circled numbers on the diagnostic table.

1. The scan position refers to the Tech 2 scan tool FUEL TRIM DATA LIST that will be displayed in order.

2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a

value that is being sensed or being issued by the PCM.

3. TYPICAL DATA VALUE is separated into two parts. T hese displayed values are typical of a normally operating

vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a

fault. The ENGINE RUNNING data should be compared to the IGNITION ON data as a diagnostic check to

make sure the component or the system is operating properly.

4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON,

and the engine OFF. The temperature sensors should be compared to the actual temperatures by letting the

sensor stabilise overnight and then comparing their values. A difference of 3 to 5° C from the actual

temperature may indicate a problem with the sensor. Use the diagnostic aids table for that sensor to compare

the resistance to temperature values.

Some ON or OFF switches may display an abnormal state. If the table states this position is abnormal, than

this may be caused by an open or short to earth, depending upon the normal state of the switch. Refer to the

proper Section for more information on diagnosis.

5. ENGINE RUNNING typical data values are an average of display values recorded from normally operating

vehicles at norm ally operating tem perature. T hey ar e intended to represent what a norm ally func tioning system

would typically display.

TECH 2 SCAN TOOL: FUEL TRIM DATA

TYPI CAL D ATA VALUE !

SCAN POSITION " UNITS DISPL AYED# IGNITION ON $ ENGINE RUNNING %

ENGINE SPEED RPM 0 RPM ± 100 RPM FROM DESIRED RP M (

± 50 RPM IN DRIVE)

DESIRED IDLE S PEED RPM 650 RPM PCM IDLE COMMAND (VARIES WITH

TEMPERATURE)

ENGINE COOLANT

TEMPERATURE (ECT) °C VARIES 96°C

IAT DEGREES C VARIES VARIES

MAP SENSOR kPa VARIES VARIES

MAP SENSOR VOLTS VOLTS 4.5 VOLTS 4.5 VOLTS

MASS AI R FLOW GRAM /SEC 0 g/s 5 -10 g/s

MAF SENSOR FREQUENCY Hz 0 Hz 2600-2900 Hz

BARO kPa VARIES VARIES

BARO SENSOR VOLTS VOLTS 4.5 VOLTS 4.5 VOLTS

THROTTLE POSI TI ON 0-100 % 0 % 0 %

THROTTLE POSITION SENSOR VOLTS 0.32 V 0.47 V

AIR FUEL RA TI O % 14.7:1 14.7: 1

FUEL SYSTEM STATUS OPEN LOOP/

CLOSED LOOP OPEN LOOP CLOSED LOOP

ENGINE LOA D % 0% 1%

LEFT HO2S SENSOR READY

(BANK 1) YES/NO NO YES

RIGHT HO2S SENSOR READY

(BANK 2) YES/NO NO YES

LEFT HO2S SENSOR

(BANK 1) mV 447m V 100-1000 mV AND VARYING

RIGHT HO2S SENSOR

(BANK 2) mV 447m V 100-1000 mV AND VARYING

LEFT SHORT TERM FUEL TRIM

(BANK 1) % +0% to -0% +10% to -10%

RIGHT SHORT TERM FUEL TRIM

(BANK 2) % +0% to -0% +10% to -10%

LEFT LONG TERM FUEL TRIM

(BANK 1) % +0% to -0% +10% to -10%

RIGHT LONG TERM FUEL TRIM

(BANK 2) % +0% to -0% +10% to -10%

FUEL TRIM CELL CELL # 0 17

FUEL TRIM LEARN YES/NO NO YES

LEFT STFT AVERAGE

(SHORT TE RM FUE L T RIM) % 0% 0%

RIGHT STFT AVERAGE

(SHORT TE RM FUE L T RIM) % 0% 0%

LEFT LTFT AVERAGE

(LONG TERM FUEL TRIM) % 0% 0%

RIGHT LTFT AVERAGE

(LONG TERM FUEL TRIM) % 0% 0%

INJECTION PULSE B ANK 1 mS 3.00 - 3.50 m S

INJECTION PULSE B ANK 2 mS 3.00 - 3.50 m S

SPARK ADVANCE DEGREES 0°BTDC 14° BTDC

KNOCK RET ARD DEGREE S 0° 0°

FUEL TRIM DIAGNOSTIC INHIBIT YES/NO YES YES

TIME FROM START HH:MM:SS VARIES WITH

ENGINE RUN T IME VARIES WITH ENGINE RUN TIME

TECH 2 SCAN TOOL: FUEL TRIM DATA DESCRIPTIONS

An explanation for each data m es sage displayed on the Tech 2 s can tool is listed below. This inform ation will assist

in tracking emission or driveability problems, since the displays can be viewed while the vehicle is being driven.

Refer to the Powertrain OBD Sy stem Check for additional information.

ENGINE SPEED: Tech 2 Displays a range of 0 to 9999 RPM

The engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired

idle under various engine loads with engine idling.

DESIRED IDLE SPEED: Tech 2 Displays a range of 0 to 3175 RPM

The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the

engine at the desired idle speed.

ENGINE COOLANT TEMPERATURE: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)

The Engine Coolant Temperature (ECT) sensor is mounted in the cylinder head of the left bank. The PCM apples

5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature

changes. W hen the sensor is cold (internal r esistance high), the PCM m onitors a high s ignal voltage and interprets

the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases

and the PCM interprets the lower voltage as a warm engine.

IAT: Tech 2 Displays a range of -39°C to 104°C (-38°F to 284°F)

The PCM converts the resistance of the Intake Air Temperature sensor to degrees.The PCM uses the Intake Air

Temperature (IAT) in order to adjust fuel delivery and spark timing according to incoming air density.

MAP: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.0 volts

The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from engine

load, and speed changes. As the intake manifold pressure increases, the intake vacuum decreases resulting in a

higher MAP sensor voltage and kPa reading. The PCM uses the MAP s ensor signal for the f ollowing: (1) Updating

the BARO reading; (2) Enabling factor for several of the diagnostics.

MAF: Tech 2 Displays a range of 0 to 10,192 Hz

The signal that is sent from the Mass Air F low ( MAF) sensor to the PCM is in the form of a frequenc y output. This

frequency output changes as the demand of engine air intake changes.

MASS AIR FLOW: Tech 2 Displays a range of 0 to 246 Grams/Sec

The Mass Air Flow (MAF) sensor measures the change in the intake air flow which results from engine load and

speed changes. As intake air flow increases, the air in the inlet manifold also increases and addition fuel is

required.

BARO: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.00 Volts

The Barometric Pressure reading is determined from the MAP sensor signal. The PCM monitors the MAP signal

during key up and Wide-Open Throttle (WOT) conditions. The Barometric Pressure compensates for altitude

differences.

TPS ANGLE: Tech 2 Displays a range of 0 to 100%

Computed by the PCM from the TP sensor voltage. The TP angle should read 0% at idle to greater than 80% at

Wide Open Throttle.

TPS VOLTAGE: Tech 2 Displays a range of 0 to 5.10 Volts

Used by the PCM to determine the amount of throttle demanded by the driver. The TPS voltage should read

between 0.25 - 1.25 volts at idle to greater than 4 volts at wide open throttle.

AIR /FUEL RATIO: Tech 2 Displays a range of 0.00 : 99.99

The Air Fuel ratio is determined from the Heated Oxygen sensor output. The PCM uses the fuel trim to adjust

fueling to attempt to maintain an Air Fuel Ratio of 14.7:1. A lower value indicates a richer commanded air fuel

mixture while a higher value indicates a leaner mixture.

FUEL SYSTEM STATUS: Tech 2 Displays “OPEN LOOP” or “CLOSED LOOP”

Closed Loop indicates that the PCM is controlling f uel delivery according to oxygen sensor voltage. In Open Loop,

the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on TP sensor, engine

coolant, and MAF sensor inputs only.

ENGINE LOAD: Tech 2 Displays a range of 0% to 100%

The PCM calculates the engine load from engine speed and MAF sensor readings. The Engine Load increases

with an increase in RPM or airflow.

LEFT HO2S SENSOR READY (BANK 1) / RIGHT HO2S SENSOR READY (BANK 2): Tech 2 Displays “YES”

or “NO”

Indicates if the HO2S sensors have reached operating temperature.

LEFT HO2S SENSOR (BANK 1) / RIGHT HO2S SENSOR (BANK 2): Tech 2 Displays a range of 0 to 1000 mV

The HO2S Bank 1 and Bank 2 Sensors parameter represents the fuel control exhaust oxygen sensor output

voltage. The voltage fluctuates constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich

exhaust) while operating in Closed Loop.

LEFT SHORT TERM FUEL TRIM / RIGHT SHORT TERM FUEL TRIM: Tech 2 Displays the Percentage

The Short Term Fuel Trim represents a short-term correction to fuel delivery the PCM makes in response to the

amount of tim e the fuel control ox ygen sensor voltage spends above or below the 450 mV threshold. If the oxygen

sensor voltage mainly remains less than 450 mV, indicating a lean air/fuel mixture, short term fuel trim

increases into the positive range above 0% and the PCM adds fuel. If the oxygen sensor voltage stays mainly

above the threshold, the short term fuel trim decreases below 0% into the negative range. The PCM reduces the

fuel delivery in order to com pensate for the indicated rich condition. Under certain conditions such as an extended

idle and a high ambient temperature, the canister purge may cause the Short Term Fuel Trim to read in the

negative range during normal operation. The Fuel Trim values at maximum authority may indicate an excessively

rich or lean system.

LEFT LONG TERM FUEL TRIM / RIGHT LONG TERM FUEL TRIM: Tech 2 Displays the Percentage

The PCM derives the Long Term Fuel Trim from the Short Term Fuel Trim value. The Long Term Fuel Trim

represents a long-term correction of fuel delivery. A value of 0% indicates that the fuel delivery requires no

compensation in order to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0%

indicates that the fuel system is rich and the PCM is reducing the fuel delivery (decreased injector pulse width). A

positive value significantly greater than 0% indicates that a lean condition exists and the PCM compensates by

adding f uel (increased injector pulse width). Fuel tr im values at m aximum authority indicates an excess ively rich or

lean system.

FUEL TRIM CELL: Tech 2 Displays a range of 0 to 23

The PCM determ ines fr om MAP and RPM inputs which f uel cell to operate the engine in. A plot of RPM vs MAP is

broken into 24 cells. The fuel trim cell displayed on the scan tool is the cell that the engine is operating under.

FUEL TRIM LEARN: Tech 2 displays “YES” or “NO”

When conditions are appr opriate f or enabling long term f uel trim corr ections, the scan tool displays ENABLED. This

indicates that the long term fuel trim is responding to the short term fuel trim. If the scan tool displays DISABLED,

then long term fuel trim will not respond to changes in short term fuel trim.

LEFT SHORT TERM FUEL TRIM AVERAGE / RIGHT SHORT TERM FUEL TRIM AVERAGE: Tech 2 Displays

the Percentage

This parameter indicates the average of the short term fuel trim cells. The short term fuel trim cells are rated

(Weighted) f or the amount of which they are used. F or ex ample, the PCM rates an idle c ell higher than a wide open

cell. If a fueling m alfunc tion is occurr ing in the idle cell and the wide open cell, the average would be mor e affec ted

by the idle cell. A negative value significantly below 0% indicates that the fuel system is rich and the PCM is

reducing the fuel delivery (decreased injector pulse width). A positive value significantly greater than 0% indicates

that a lean condition ex ists and the PCM is com pensating by adding fuel (incr eased injec tor pulse width). When the

average of the cells reaches a predetermined high or low, a fuel trim DTC sets.

LEFT L ONG T ERM FUEL T RIM AVERAGE / RIGHT LONG T ERM F UEL TRIM AVERAGE: Tech 2 Displays the

Percentage

This parameter indicates the average of all long term fuel trim cells. The short term fuel trim cells are rated

(Weighted) for the am ount of which they are used. For exam ple, an idle c ell is rated higher than a wide open cell. If

a f ueling malf unction occurs in the idle c ell and the wide open cell, the aver age would be m ore affec ted by the idle

cell than the wide open cell. A negative value significantly below 0% indicates that a lean condition exists and the

PCM compensates by adding fuel (increased injector pulse width). When the average of the cells reach a

predetermined high or low, a fuel trim DTC sets.

INJECTION PULSE BANK 1 / BANK 2: Tech 2 Displays a range of 0 to 100 m/sec

The Inj ector average indicated the am ount of tim e the PCM com mands each injector ON during each engine cycle.

A longer injec tor puls e with causes m or e fuel to be deliver ed. The Inj ector Puls e Width increas es with an increas ed

engine load.

SPARK ADVANCE: Tech 2 Displays a range of -64° to 64°

The scan tool displays the amount of degrees the PCM commands the spark advance on the ignition control (IC)

circuit. The PCM computes the desired spark advance using the following: (1) Engine coolant temperature; (2)

Engine speed (RPM); (3) Load; (4) Vehicle speed. The PCM adjusts the timing.

KNOCK RETARD: Tech 2 Displays a range of 0.0° to 16°

Knock Retard indicates the am ount of s park the PCM rem oves f rom the IC spark advance in response to the signal

from the knock sensor.

FUEL TRIM DIAGNOSTIC INHIBIT: Tech 2 Displays “YES” or “NO”

The s can tool displays No when the PCM determines that certain par am eters pr ohibit the Fuel Trim diagnostic from

running. The scan tool displays Yes when the PCM determines that the Fuel Trim diagnostic is allowed to run.

TIME FROM START: Tech 2 Displays 0:00:00

Indicates the hours, minutes and seconds the engine has been running.

TECH 2 SCAN TOOL: FREE ZE FRAME / FAILURE RECORDS DATA DISPLAY

The Tech 2 scan TOOL FREEZE FRAME / FAILURE RECORDS in the table may be used for identification of

conditions at time of DTC set

1. After completing the Powertrain OBD System Check

2. If DTC(s) are set, review Freeze Frame/Failure Records.

A TECH 2 SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM

SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY TECH 2 SCAN TOOL CAN

RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.

Test Description The numbers below refer to the circled numbers on the diagnostic table.

1. The scan pos ition refers to the Tec h 2 scan tool FREEZE F RAME / FAILURE RECORDS that will be displayed

in order.

2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a

value that is being sensed or being issued by the PCM.

3. T he values shown in the DAT A VALUE c olumn indic ates the c aptur ed data values at the time the DTC was set.

These values are based on KEY ON time, and/or ENGINE RUN time and will vary.

TECH 2 SCAN TOOL: FREEZE FRAME / FAILURE RECORDS DATA DISPLAY

SCAN POSITION " UNITS DISPLAYED # DATA VALUE !

ENGINE SPEED RPM 0 RPM

DESIRED IDLE SPEED RPM 0 RPM

ENG. COOLANT TEMP (E CT) DEGREES C VARIE S

START UP ECT DEGREES C VARIES

THROTTLE POSI TI ON 0-100 % 0 %

ENGINE LOAD % %

BARO kPa kPa

BARO SENSOR VOLTS VOLTS VOLTS

MAP SENSOR kPa kPa

MAP SENSOR VOLTS VOLTS VOLTS

MASS AIR FLOW GRAM /SEC GRAM /SEC

FUEL SYSTEM STATUS OPEN LOOP/

CLOSED LOOP OPEN LOOP/

CLOSED LOOP

LEFT SHORT TERM FUEL TRIM

(BANK 1) % +0% to -0%

RIGHT SHORT TERM FUEL TRIM

(BANK 2) % +0% to -0%

LEFT LONG TERM FUEL TRIM

(BANK 1) % +0% to -0%

RIGHT LONG TERM FUEL TRIM

(BANK 2) % +0% to -0%

INJECTION PULSE BANK 1 m S mS

INJECTION PULSE BANK 2 m S mS

AIR FUEL RA TI O % 14.7: 1

TRANSMISSION RANGE PARK, REVERSE,

NEUTRAL, DRIVE 4

OD, DRIVE 3 / D,

DRIVE 2, DRIVE 1,

INVALID

PARK, REVE RSE, NE UTRAL, DRI VE 4 OD, DRIVE 3 / D, DRIVE

2, DRIVE 1, INVALID

CURRENT GEAR 1, 2,3,4 1,2,3,4

AT Output S peed ( Auto Trans) RPM RPM

TCC BRAKE SWITCH ON / OFF ON / OFF

TCC SOLENOID ON / OFF ON / OFF

TCC PWM ON / OFF ON / OFF

VEHICLE SPEED km/h km /h

TIME FROM START TIME 0:00:00

FIRST ODOMETER km km

LAST ODOMETER km km

FAIL COUNT E R # #

PASS COUNTER # #

NOT RAN COUNTER # #

TECH 2 SCAN TOOL: PI M DATA DISPLAY

A TECH 2 SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM

SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY TECH 2 SCAN TOOL CAN

RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.

Only the param eters listed are used of the VT Series II Service Information for diagnosis. For more description on

the values and use of the Tech 2 scan tool to diagnosis PIM inputs, refer to the applicable diagnosis table in this

Section. If all values are within the range illustrated, refer to SYMPTOMS Tables in Section 6C3-2B of the VT

Series II Service Information.

Test Description: The number(s) below refer to the number(s) on the Tech 2 Scan PIN Data table.

1. The Tec h 2 sc an tool FO: PIM DATA LIST will display scan position's that will be displayed in order. The T ech

2 sc an tool will display nine (9) scan pos ition parameters at a time. T he down # button will scroll down through

all of the scan positions one at a time. After TIME FROM START parameter is displayed, pressing the down

arrow button again, will display scan position parameters starting at the top of the list again.

2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a

value that is being sensed or being issued by the PCM.

3. TYPICAL DATA VALUE is separated into two parts. T hese displayed values are typical of a normally operating

vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a

failure. The ENGINE RUNNING data should be compared to the IGNITION ON data as a diagnostic check to

make sure the component or system is operating properly.

4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON,

and engine stopped. Temperature sensors should be compared to the actual temperatures by letting the

sensor stabilise overnight and then comparing their values. A difference of 3-5° from the actual temperature

may indicate a problem with the s ens or. Us e the diagnos tic aids table f or that s ensor to c ompare the r esis tanc e

to temperature values.

5. ENGINE RUNNING typical data values are an average of display values recorded from normally operating

vehicles at norm ally operating tem perature. T hey ar e intended to represent what a norm ally func tioning system

would typically display.

TECH 2 SCAN TOOL: PIM DATA DISPLAY

TYPICAL DATA VALUE !

SCAN POSITION " UNITS DISPL AYED #

IGNITION ON $ ENGI NE RUNNING %

STARTER RELAY OFF/ON OFF OFF

FUEL CONTINUE OFF/ON ON ON

FUEL DISABLE TIME-OUT OFF/ON OFF OFF

FUEL DISABLE CYCLE IGN OFF/ON OFF OFF

AUTO LEARN ACTIVE OFF/ON OFF OFF

PIM THEFT DETERRENT

COMMUNICATION LOST OFF/ON OFF OFF

PASSWORD LEARNING OFF/ON OFF OFF

PIM DTC STATUS NO DTC

DTCs SET NO DT C NO DTC

SOFTW ARE VERSION FOUR DIGIT NUMBER

(VARIES WITH PCM

SOFTW ARE

UPDATES)

5.5 5.5

PIM COMMUNICATION DISABLE OFF/ON OFF OFF

A/C CLUTCH OFF/ON OFF OFF

CHECK POWERTRAIN

LAMP (CPL) OFF/ON ON OFF

LOW COOLANT LEVEL YES/NO NO NO

OIL PRESS URE SENSOR OFF/ON OFF ON

ENGINE OI L CHA NGE OKAY / SERVICE

REQUESTED OKAY OKAY

ENGINE OIL LIFE RESET OFF/ON OFF OFF

SHIFT PATTERN ECONOMY / POWER ECONOMY ECONOMY

LOW SPEED FAN REQUEST OFF/ON OFF OFF

LOW SPEED FAN RUN ON YES/NO NO NO

TECH 2 SCAN TOOL: PIM DATA DISPLAY DESCRIPTIONS

A list of ex planations for each data m essage disp layed on the Tech 2 sc an tool begins as follows. This infor mation

will assist in track ing emission or driveability problems, since the displays can be viewed while the vehicle is being

driven. Refer to Powertrain OBD System Check for additional information.

START RELAY: Tech 2 Displays "OFF" or "ON"

The scan tool displays ON when the Start Relay is enabled.

FUEL CONTINUE: Tech 2 Displays "OFF" or "ON"

Tech 2 displays ON if the proper Theft Deterrent signal is sent from the PIM to the PCM for fuel control.

FUEL DISABLE TIME-OUT: Tech 2 Displays "OFF" or "ON"

Tech 2 displays ON when the PCM sends a message back to the PIM indicating PCM is satisfied with Theft

Deterrent signal and is allowing fuel injection.

FUEL DISABLE CYCLE IGN: Tech 2 Displays "OFF" or "ON"

Tec h 2 displays OFF when the PCM secur ity has failed. Engine will not be fueled until the ignition has been cycled

from ON to OFF to ON.

AUTO LEARN ACTIVE: Tech 2 Displays "YES" or "NO"

Tech 2 displays YES if the PCM is in automatic password learning mode.

PIM THEFT DETERRENT COMMUNICATION LOST: Tech 2 Displays "YES" or "NO"

Tech 2 indicates YES if there is a Theft Deterrent communication loss between the PIM and PCM.

PASSWORD LEARNING: Tech 2 Displays "YES" or "NO"

Tech 2 displays YES if the PIM is in a current Password Learn m ode. PCM will learn CLASS II security code from

PIM on the next ignition cycle.

PCM DTC STATUS: Tech 2 Displays “NO DTCs” or “DTCs SET”

Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC (s) are or are not set.

PIM DTCs STATUS: Tech 2 Displays “NO DTCs” or “DTCs SET”

Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC (s) are or are not set.

SOFTWARE VERSION: Tech 2 Displays Number of Software ID in PCM.

PIM COMMUNICATION DISABLE - Tech 2 Displays "ON" or "OFF"

A/C CLUTCH: Tech 2 Displays "ON" or "OFF"

Represents the commanded state of the A/C clutch control relay. Clutch should be engaged when ON is displayed.

CHECK POWERTRAIN MALFUNCTION INDICATOR LAMP (MIL) or Check Powertrain Lamp (CPL): Tech 2

Displays "OFF" or "ON"

Indicated if the instrument panel (CPL) is ON or OFF.

LOW COOLANT LEVEL: Tech 2 Displays "NO" or "YES"

This is an indication to the PCM that the coolant level is low. If the coolant level is low, the PCM will turn on the

Low Coolant Lamp.

OIL PRESSURE SENSOR: Tech 2 Displays "OFF" or "ON"

This is an indication to the PC M if the oil pressur e is low. If the oil pressu re is low, the PCM will turn ON a Low Oil

Warning Lamp.

ENGINE OIL CHANGE: The Tech 2 Displays “OKAY” or “SERVICE REQUESTED”

The scan tool will display the status of the engine oil change condition.

ENGINE OIL LIFE RESET: Tech 2 Displays "OFF" or "ON"

The scan tool will display ON when the SERVICE REQUESTED is indicated on the instrument panel. The reset

function can be performed at the instrument panel trip computer.

SHIFT PATTERN: Tech 2 Displays “ECONOMY” or “POWER”

This display shows the state of the ECONOMY/POWER switch.

LOW SPEED FAN REQUEST: Tech 2 Displays "ON" or "OFF”

Indicates if the engine cooling fan low speed relay has been commanded ON or OFF.

LOW FAN RUN ON: Tech 2 Displays "NO" or "YES"

The scan tool will indicate NO if the PCM is commanding the BCM to enable the Low Fan Relay when the key is

turned OFF.

TECH 2 SCAN TOOL: AUTOMATIC TRANSMISSION DATA

Use the scan tool data values under the following conditions:

• The Powertrain On-Board Diagnostic (OBD) System Check is complete.

• The on-board diagnostics are functioning properly .

• No DTCs are present.

The following values represent a typical display recorded from a properly functioning system.

IMPORTANT: Do not use a Tech 2 scan tool that displays faulty data. Report the condition to the scan tool

manufacturer. The use of a faulty scan tool can result in m isdiagnosis and the unnecessary replacement of parts.

Only the parameters listed below are used in this manual for diagnosing.If a scan tool displays other parameters,

the values are not recommended by Holden for use in diagnosis.

The following scan tool values below were recorded under the following conditions:

• Engine at Idle

• Upper radiator hose hot

• Closed throttle

• Transmission in PARK

• Closed Loop operation

• Accessories OFF

• Brake pedal not applied

TECH 2 SCAN TOOL: AU TOMATIC TRANSMISSION DATA

SCAN TOOL PARAMETER DATA LIST*

UNITS TYPICAL DATA VALUE

1-2 Shift Ti me F0, F1 Seconds Varies

1-2 Solenoid A F0, F1 On/Off On

1-2 TAP Cell (4-16) F1 kPa/PSI Varies

2-3 Shift Ti me F0, F2 Seconds Varies

2-3 Solenoid B F0, F1, F2 On/ Off On

2-3 TAP Cell (4-16) F2 kPa/PSI Varies

3-2 Downshift Solenoi d F0 On/Off On

3-4 Shift Ti me F0 Seconds Varies

A/C Clut ch (Air Condit i oni ng) F0 On/Off Off

Adapt Shi f t Stat us F0, F1, F2 E nabl ed/Disabled Disabled

AT Output S peed (Autom atic Trans mis sion) F0 RPM 0

Battery V ol tage F0 Vol t s 12-14 V ol t s

Commanded Gear F0, F1, F2 1, 2, 3, 4 1

Current TAP Cell F1, F2 4-16 Varies

Current TAP Memory F1, F2 -16 to +16 Varies

DTC Status - No DTC/DTC Set No DTC

Engine Coolant Temperature F0 ° C Varies

Engine Speed F0 RPM V ari es (640-680)

Engine Torque F0 Nm Varies

Intake Air Tem perat ure F0 ° C Varies

Latest Shift F0 Seconds Varies

Actual P CS (P ressure Control Solenoid) F0 Milliamps Varies

(1055-1074 Milliamps)

Commanded PCS (Pressure Control Solenoid) F0 Milliam ps Varies

(1055-1074 Milliamps)

PCS Duty Cyc l e (Pressure Control Solenoi d) F0 Percent Varies (62-64%)

Shift Pattern F0 Economy/Power/Cruise Economy

Speed Ratio F0 Ratio 8. 00: 1

TCC Brake Switch (Torque Converter Clut ch) F0 Open/Cl osed Cl osed

TCC PWM (Torque Converter Clutch) F0 Percent 0%

TCC Solenoid (Torque Converter Cl utch) F0 On/Off Off

TCC Mode F0 0-5 0

TCC Slip Speed (Torque Converter Clutc h) F0 RPM +/- 50 RPM

from Engine Speed

TFP Switch A/B/C F0 Open 12 V/ Cl osed 0 V Open 12 V/ Closed 0

V/Open 12 V

TFT Sensor (Transmi ssion Fluid Tem perature) F0 Volts Varies

Throttle Position F0, F1, F2 Percent 0%

Throttle P osition S ensor F0 Vol t s 0. 49-0. 55 V

Time From Start F0 Hr/ Min/ S ec Vari es

Transm i s sion Fluid Temperature F0 ° C Vari es

Transm ission Hot Mode F0 On/Off Of f

Transm i s sion Range (TR) F0 Park/Neutral, Reverse,

Park/Neutral, Drive 4

O/D, Drive 3/D, Drive 2,

Drive 1

Park/Neutral

TR Switch A (Transmi ssion Range) F0 Open 12 V/ Cl osed 0 V Closed 0 V

TR Switch B (Trans mis sion Range) F0 Open 12 V/Closed 0 V Open 12 V

TR Switch C (Transmis sion Range) F0 Open 12 V /Closed 0 V Open 12 V

TR Switch P (Transmi ssion Range) F0 Open 12 V/ Cl osed 0 V Closed 0 V

Vehicle Speed F0 km/h 0

*Data List Legend

• F0: Transmiss i on Data

• F1: 1-2 Adapt Data

• F2: 2-3 Adapt Data

TECH 2 SCAN TOOL: PIM DATA DISPLAY DESCRIPTIONS

1-2 SHIFT TIME

Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 1-2 shift. The shift time is

based on the engine RPM drop after the commanded 1-2 shift. This value is only accurate if the shift was

adaptable.

1-2 SOLENOID A

Displays ON or OFF. This parameter is the commanded state of the 1-2 shift solenoid valve. ON represents a

commanded energised state (current is flowing through the solenoid). OFF represents a non-commanded state

(current is not flowing through the solenoid).

1-2 TAP CELL (4-16)

Displays kPa. T his par ameter dis plays the am ount of pres s ure var ied f r om a calibr ated base line pres su re for shif ts .

Each TAP Cell is based on a calibrated shift torque value. Each TAP Cell value is calculated from the last shift

time. This cell pressure is used in addition to the calibrated base line pressure to adjust the application of a clutch

or band during the next shift.

2-3 SHIFT TIME

Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 2-3 shift. The shift time is

based on the engine RPM drop after the commanded 2-3 shift. This value is only accurate if the shift was

adaptable.

2-3 SOLENOID B

Displays ON or OFF. This parameter is the commanded state of the 2-3 shift solenoid valve. ON represents a

commanded energised state (current is flowing through the solenoid). OFF represents a non-commanded state

(current is not flowing through the solenoid).

2-3 TAP CELL (4-16)

See 1-2 Tap Cell (4-16)

3-2 DOWNSHIFT SOLENOID

Displays ON or OF F. T his param eter indicates if the 3-2 shif t solenoid valve ass embly is curr ently com m anded ON

or O FF. The solenoid com m anded s tate is based on the tr ansm iss ion tem perature. T he solenoid will change s tates

during a 3-2 downshift to regulate the appropriate pressure. The commanded state of the solenoid occurs at

approximately 48 km/h with a throttle increase.

3-4 SHIFT TIME

Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 3-4 shift. The shift time is

based on the engine RPM drop after the commanded 3-4 shift. This value is only accurate if the shift was

adaptable.

A/C CLUTCH

Displays ON or OFF. This param eter indic ates the com manded s tate of the A/C contr ol relay. The clutch should be

engaged when ON displays.

ADAPT SHIFT STATUS

Displays ENABLED or DISABLED. ENABLED indicates that the proper operating conditions were all within the

proper operating r ange during the last shift and that the s hift time was ac curate. This s hift inform ation is then used

through the adaptive function in order to update the adapt cells. DISABLED indicates that not all of the operating

conditions were met in order to enable this function and that the adapt cells were not updated.

AT OUTPUT SPEED (AUTOMATIC TRANSMISSION)

Displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the transmission output shaft

expressed as revolutions per minute.

BATTERY VOLTAGE

Displays a range of 0.0-25.5 V. This represents the system voltage measured by the PCM at its ignition feed.

COMMANDED GEAR

Displays 1, 2, 3 or 4. This parameter indicates the current commanded state of the shift solenoids.

CURRENT TAP (TRANSMISSION ADAPTIVE PRESSURE) CELL

Displays a TP cell range of 0-16. This parameter indicates the current throttle position cell used for line pressure

modification (adaptation).

CURRENT TA P (TRANSMISSION ADAPTIVE PRESSURE) MEMORY

Displays a range of -16 to +16 psi. T his param eter is the am ount of pressure that is added to base line press ure to

adjust the holding effort of a clutch or band, while shifting.

ENGINE COOLANT TEMPERATURE

Displays a range of - 40°C to 151° C. This param eter is the input signal of the Engine Coolant T emperatur e sensor

(ECT). The engine coolant temperature is high (151° C) when the signal voltage is low (0 V), and the engine

coolant temperature is low (-40°C) when the signal voltage is high (5 V).

ENGINE SPEED

Displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the engine expressed as

revolutions per minute.

ENGINE TORQUE

Displays a range of 0-9999 N.m. This parameter indicates the amount of torque that is delivered from the engine.

INTAKE AIR TEMPERATURE

Displays a range of -40°C to 215°C. The IAT sensor is a thermistor that is used to monitor the temperature of the

air enter ing the intake m anif old. The PCM applies 5 volts to the sens or on a 5 volt ref erenc e circuit. When the air is

cool, the resistanc e in the sensor will be high. If the air is warm , the sensor resistance will be low and the PCM will

sense a low voltage signal. The PCM converts the signal of the IAT sensor to degrees Celsius. Intake air

temperature is used by the PCM to adjust fuel delivery and spark timing.

LATEST SHIFT

Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last upshift. This value is only

accurate if the shift was adaptable.

ACTUAL PCS (PRESSURE CONTROL SOLENOID)

Displays a range of 0.00-1.10 am ps. This parameter is the actual current of the pr essure control s olenoid circuit at

the control module. Zero amp (no current flow) indicates actual higher line pressure. Actual lower line pressure is

indicated by 1.1 amps (high current flow).

COMMANDED PCS (PRESSURE CONTROL SOLENOID)

Displays a range of 000-1100 Milliam ps . This param eter is the com m anded c urrent of the pressure control solenoid

circuit. Zero Milliamps (no current flow) indicates commanded higher line pressure. Commanded lower line

pressure is indicated by 1100 Milliamps (high current flow).

PCS DUTY CYCLE (PRESSURE CONTROL SOLENOID)

Displays a range of 0- 100%. T h is par ameter is the c ommanded state of the pr es sur e c ontrol s olenoid ex pres s ed as

a percent of energized ON time. Zero percent indicates zero ON time (non-energized) or no current flow.

Approximately 60% at idle indicates maximum ON time (energized) or high current flow.

SHIFT PATTERN

Displays ECONOMY, POWER, CRUISE. This parameter indicates the shift pattern that is currently being used.

Through electronic operation, the PCM c an change the shift pattern f or ECONOMY (norm al driving), POW ER (late

upshift points, reduced shift times, and TCC apply in third and fourth), and CRUISE (earlier downshifts and later

upshift points).

SPEED RATIO

Displays a range of 0.00:1 to 8.00:1. T his parameter indic ates engine speed divided by transm ission output speed.

This value is used to estimate transmission gear ratio.

TCC BRAKE SWITCH

Displays OPEN or CLOSED. T his parameter indicates the state of the br ake switch circ uit input. OPEN indicates a

zero voltage input (brake switch open, brake pedal applied). CLOSED indicates a B+ voltage input (brake switch

closed, brake pedal released).

TCC PWM

Displays a range of 0-100%. T his param eter is the com m anded percentage of ON tim e of the TCC PWM s olenoid.

Approxim ately 90 percent repr esents an ON (energized) com manded st ate. Zero percent represents an OFF (non-

energized) commanded state. This commanded state is applied at a vehicle speed between approximately 0-16

km/h.

TCC SOLENOID

Displays ON or OFF. This parameter is the commanded state of the TCC solenoid. ON indicates a commanded

energized state ( curr ent is f lowing through the s olenoid). OF F indicates a c om m anded non-energized state (c urrent

is not flowing through the solenoid). This commanded state occurs at various vehicle speeds between applications.

TCC MODE

Displays a range of 0 through to 5. Zero (0) or OFF Mode indicates that the PCM commands the TCC OFF at a

calibrated minimum throttle. The calibrated minimum throttle is different at low vehicle speeds than it is at high

vehicle speeds.

OFF Mode is also active when the transm ission is in the wrong gear range, the engine or the transm ission is cold,

the brake input indicates that the brakes are ON, a downshift or upshift is initiated, the engine is at idle, the

transmission is in HOT Mode or a misfire is detected. One (1) or RELEASE Mode indicates that the PCM

commands the release of the TCC. Two (2) or Apply Mode indicates that the PCM commands the apply of the

TCC.

Application pressure varies based on normal or performance operations, hot conditions or if the cruise control is

active. APPLY Mode is used under normal driving conditions. All apply pressure is dependent on throttle position

and vehicle speed.

Three (3) or APPLY ENABLE Mode indicates that enabling conditions are met for applying the TCC (enabling

conditions include vehicle speed, gear selection, transmission temperature, throttle angle, brake switch status,

etc.). Four (4) or LOCKED Mode indic ates that the PCM com m ands full c apacity of the TCC when the transm iss ion

is in fourth gear and the vehicle speed is greater than a calibrated value.

When variable TCC apply pressure stops (APPLY Mode), maximum TCC pressure is used. Five (5) or COAST

Mode indicates that the PCM com mands apply of the TCC when the transmission is in fourth gear and the throttle

and vehicle speed are not high enough to enable APPLY Mode, but high enough to keep the TCC applied. W hen

COAST Mode is active, TCC apply pressure is set to a predetermined amount.

TCC SLIP SPEED (TORQUE CONVERTER CLUTCH)

Displays a range of -4080 to 4079 RPM. This parameter is the difference between transmission output speed and

engine speed. A negative value indicates that the engine speed is less than the output speed (deceleration).

A positive value indicates that the engine speed is greater than the output speed (acceleration). A value of zero

indicates that the engine speed is equal to the output speed (TCC applied).

TFT SENSOR (TRANSMISSION FLUID TEMPERATURE)

Displays a range of 0.00- 5.00 V. When the tr ansmis sion f luid is co ld, the sens or res ist ance is high and the PCM will

sense high signal voltage. As the transmission fluid temperature warms to a normal operating temperature, the

sensor resistance becomes less and the voltage decreases.

TFP SWITCH A/B/C

Displays Open 12 V/Closed 0 V, Open 12 V/Closed 0 V, Open 12 V/Closed 0 V. These parameters are the three

inputs fr om the Autom atic T rans m ission Fluid Pr essur e Manual Valve Position Switch Assem bly. Closed represents

a 0 voltage signal. Open represents a B+ voltage signal.

THROTTLE POSITION

Displays a range of 0-100%. The TP angle is computed by the PCM from the TP Sensor voltage. The TP angle

should read 0% at idle and 100% at Wide Open Throttle (WOT).

THROTTLE POSITION SENSOR

Displays a range of 0.00-5.00 volts. The TP Sensor is used by the PCM to determine the amount of throttle

demanded by the driver. Voltage is below 1 volt at idle and above 4 volts at Wide Open Throttle (WOT).

TIME FROM START

Displays a range of 0:00:00 to 18:12:15 hr/min/sec. This parameter measures how long the engine has been

operating. When the ignition switch is turned OFF, the value is reset to zero.

TRANSMISSION FLUID TEMPERATURE

Displays a range of -40°C to 151°C. T his param eter is the input signal of the transm is sion fluid temper ature sensor.

Trans m ission fluid tem perature is high (151°C) when signal voltage is low (0 V) , and transm is sion fluid tem per ature

is low (-40°C) when signal voltage is high (5 Volts).

TRANSMISSION HOT MODE

Displays ON or OFF. This parameter monitors transmission temperature. On indicates that the transmission

temperature has exceeded 135°C.

TRANSMISSION RANGE (TR)

Displays PARK / NEUTRAL, REVERSE, PARK/NEUTRAL, DRIVE 4 O/D, DRIVE 3/D, DRIVE 2, DRIVE 1. The

scan tool displays the decoded pos ition of the transm iss ion Park/Neutral range s witch (PRNDL). This inform ation is

then sent to the instrument panel and is displayed to the operator.

TR SWITCH A (TRANSMISSION RANGE)

Displays OPEN 12 V/CLOSED 0 V. This param eter is the input fr om the automatic transm iss ion Park/Neutral range

switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.

TR SWITCH B (TRANSMISSION RANGE)

Displays OPEN 12 V/CLOSED 0 V. This parameter is the input from the automatic transmission PARK/NEUTRAL

range switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.

TR SWITCH C (TRANSMISSION RANGE)

Displays OPEN 12 V/CLOSED 0 V. This param eter is the input fr om the automatic transm iss ion Park/Neutral range

switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.

TR SWITCH P (TRANSMISSION RANGE)

Displays OPEN 12 V/CLOSED 0 V. This parameter is the input from the automatic transmission PARK/NEUTRAL

range switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.

VEHICLE SPEED

Displays a range of 0-255 km/h. This parameter is the input signal from the vehicle speed sensor assembly.

DIAGNOSTIC TABLES

INTRODUCTION

The diagnostic tables are designed to provide fast and efficient means of fault location for all engine and

transmission functions associated with the PCM. Each diagnostic table uses 2 pages; a table on the right side

page, and a facing page on the left side page. The left side "facing page" contains pertinent information, including

diagnostic trouble code setting parameters and circuit diagrams. The table steps are explained by the

corresponding numbered paragraph on the left side facing page.

When diagnosing any problem, always begin with THE ON-BOARD DIAGNOSTIC SYSTEM CHECK This will

lead you to the other tables. DO NOT GO DIRECT LY TO A SPECIFIC T ABLE or false diagnosis and r eplacement

of serviceable parts could result.After a fault is corrected and all DTCs have been cleared, repeat the ON-BOARD

DIAGNOSTIC SYSTEM CHECK to assure that the proper repairs have been made.

The "A" Table pages and the diagnostic trouble code diagnostics pages are constructed in a similar fashion. The

box at the top of the left page contains a wiring diagram showing the components involved in each circuit.

Immediately below the box is a brief circuit description. On the facing right-hand page a troubleshooting table for

diagnosing c onditions. Step number s on the right-hand page nex t to the ac tion boxes in the table r elate to the items

in the Test Decription on the left-hand page. These items provide an explanation of each test in the table.

The appropriate step in any of the trouble shooting table will instruct you either to make a specific repair or to

continue diagnosis. If further diagnosis is needed, the step will specify where to continue.

The Yes or No column in any diagnostic table will instruct you either to make a specific repair or to continue

diagnosis. If further diagnosis is needed, the Yes or No column will specify where to continue.

If the condition is intermittent, the trouble shooting table will direct you to the diagnostic aids on the facing page.

This section gives suggestions for diagnosing intermittent conditions and explains how some faults can occur.

Remember, tables are for solving active conditions or diagnostic trouble codes, not intermittent conditions. Use

symptom diagnosis for solving intermittent conditions.

Diagnostic Flow Table Typical

WRITING THE REPAIR ORDER

The repair order is one of the most important tools

a technician can have. Like his other tools, the

repair order must be highly accurate to give him

the greatest help.

It's up to the service adviser to supply the

technician with this highly accurate tool. Problems

begin for the technician when the repair order is

incomplete or is incorrect.

An incomplete repair order doesn't provide the

technician with a good starting point for the

diagnosis. Consequently, the technic ian m ay waste

time, using a “ shotgun” approach attem pting to find

the problem.

An incorrectly written repair order can lead the

technician down the wrong diagnostic path,

preventing him from finding the problem.

Consequently, a service adviser needs to write an

accurate and complete repair order. This is

accom plished by asking the driver these questions:

WHO? WHAT? WHEN? WHERE? and HOW?

An Incomplete Repair Order

"WHO"? QUESTIONS

"WHO"? is the first question you need to ask. As

you begin to fill out the repair order, you need to

find out who was driving the vehicle when the

problem occurred and talk directly to that person if

at all possible.

This allows you to give first-hand information on

the problem to the technician, which is critical to

diagnosing the problem. If you can't talk directly to

this person, get their name and phone number so

the technician can call the driver if needed.

"WHAT"? QUESTIONS

The next step is to find out "WHAT"? the problem

is. If it's a driveability problem, and it seems to be

complex, bring the technician who's going to work

on the vehicle into the picture if at all possible.

Allow the technician to question the driver directly,

so he can get the inf orm ation he needs to help him

diagnose the problem. Again, this is so he can get

first-hand knowledge of the problem.

If you don't involve the technician with the driver,

you need to ask if the Check Powertrain Lamp

(CPL) is ON all the time, coming ON and OFF

during the same key cycle, or is never ON.

Typical Symptomatic Diagnostic Table

This is important to the technician because this

informs him which diagnostic direction to take.

These tables are different from one another. If a

technician is f ollowing the wrong table, a lot of time

is wasted. So, ask the driver questions about the

Check Powertrain Lamp (CPL).

Other good "WHAT"? questions are. Under what

conditions did the problem occur?

Were they accelerating, decelerating, or coasting?

Were they driving in the city or on the freeway?

What were the environmental conditions? Was it

raining? snowing? hot? cold? The technician may

need to duplicate these conditions as closely as

possible if he is to find the cause of the problem.

"WHEN"? QUESTIONS

"WHEN"? questions are the next step. If the driver

says the Check Powertrain Lamp (CPL) was ON,

you need to as k when the Check Powertrain Lam p

(CPL) came ON and how long it has been ON. Is

the Check Powertrain Lamp (CPL) ON before or

during starting, or when the engine is running?

More im portant, you need to ask when the problem

first oc curred. Maybe it began after the vehicle was

serviced f or a related pr oblem or for som ething that

appears to be totally unrelated.

The technician also needs to know if the problem

has become worse. This information may give the

technician som e clues as to what the problem may

be.

"WHERE"? QUESTIONS

"WHERE"? is the next question. The location

where the problem occurs may give the technician

an idea as to what may be contributing to the

problem, such as electromagnetic interference

from overhead power lines.

"HOW"? QUESTIONS

To round out your questioning, you need to ask the

driver "HOW "? often the problem occurs. This can

give the technician direction as to what type of

system may be causing the problem: electrical,

mechanical, vacuum, etc.

Typical Diagnostic Table

SUMMARY

In summary, you need to obtain the following

information from the driver:

• Who the principal driver is.

• What the problem is.

• When the problem began.

• Where the problem occurs.

• How often the problem occurs.

Complete answers to these questions will aid the

technician in diagnosing the problem.

VERIFYING THE COMPLAINT

Engine Compartment Inspection

The most important step in diagnosing a driveability complaint is to verify the complaint. This means you have to

duplicate the problem if possible.

Start by performing an engine compartment inspection. Check the integrity of all the electrical connections and

vacuum hoses, etc. Also, check the wire routing for the possibility of Electromagnetic Interference (EMI).

Checking For Stored Diagnostic Trouble Codes

As you check for Diagnostic Trouble Codes, keep in mind that intermittent faults may not store a Diagnostic

Trouble Code. So proceed with verifying the complaint, even if no Diagnostic Trouble Codes are stored.

If a Diagnostic Trouble Code is stored, check the service bulletins for the particular vehicle you're working on.

Road Testing The Vehicle

This step is optional if the repair order states.

• The driveability problem is intermittent.

• You did not find any problems under the bonnet .

• No diagnostic trouble codes are stored.

Then you need to road test the vehicle in order to recreate the problem.

This is an important step because the problem has to be present in order to repair the problem.

Most intermittent driveability problems are repeatable. That is what road testing is all about.

Before you go on your road test, review the vehicle's ser vice histor y. This information c an give you clues as to what

may be causing the driveability problem and what you need to watch.

Read the repair order and think about what systems could possibly cause the problem. This is essential to finding

the problem. Think about how the system or systems in question works, what inputs are needed and what could

cause the problem.

Check all the inputs required for a circuit, whether the circuit actually has trouble or if you only suspect trouble. All

inputs are needed and m ust be within a "normal" r ange. You will want to pay attention to these system s and circuits

during and after the road test.

As you're road testing, put the Tech 2 scan tool in the snapshot mode so you can capture the system data when

the problem occurs.

Do not discount the other information the Tech 2 snapshot mode can supply you with.

Don't Forget The Basics

Whether or not you find anything wrong during the road test, don't forget the basics.

Electrical connections such as power feeds and earths are vital to the operation of almost all of the vehicle

systems.

No matter how good the system is, it is still working in combination with the engine. If the engine is not in good

condition, the computer system can't make up for the condition.

Compare performance problems, such as lack of power, with a comparable vehicle. This will let you know if the

driver complaint really is a problem or something that is normal.

If you can't repeat the problem, and you need more information for diagnosing, call the driver who was driving the

vehicle when the problem occurred. This type of professionalism will probably help you diagnose the problem.

EEPROM

If a vehicle is just starting to have an intermittent driveability problem and it has accumulated more than 30,000

kilometres, chances are that the EEPROM calibration is not at fault.

If the vehicle was running properly for such a long time, the original EEPROM calibrations are not the problem

since the EEPROM calibrations don't change, the chances of the EEPROM going bad are rare. There may

however be an updated EEPROM calibration for a particular condition, so check service bulletins for calibrations

updates.