SECTION 6C1-2B - SYMPTOMS – V6 ENGINE

IMPORTANT

Before p erf orming any Service O p eratio n o r ot her p roced ure describ ed in t his Sect ion , refer t o Sect ion 00

CAUTIONS AND NOTES for correct workshop practices with regard to safety and/or property damage.

W hen no diagnostic trouble codes have been set and the Tec h 2 data values are within typical ranges, you should

diagnose the condition based on the symptoms of the complaint.

This Symptom Section starts with preliminary checks that must be performed in order to diagnose by symptom.

Then, intermittent conditions are discussed. These preliminary pages provide important information to assist you

with symptom diagnosis. Next, the contents of this Section presents the various symptoms and lists a series of

checks for each.

Many of the s ymptom diagnostic s st art with a very important pr ocedur e, a vis ual/physical inspection. Always look for

the obvious first. Some situations may warrant observing the driver. Is the driver using the correct shift lever position

or riding the brake pedal? Visually check the engine, transmission and PCM connectors. Are there any

disconnected wires or incorrectly installed components? Finally, are there obvious signs that someone may have

performed incorrect repairs? These check s take very little time; they can eliminate the time spent on a broad-base

systematic diagnos is by direct ing you to the problem . If they do not reveal the problem , proceed to chec k the other

suspect systems, as shown.

The last pages of this Sec tion contain PCM connector symptom Tables. If you are diagnosing a problem , scan the

right-most column for the symptom(s) and check for the correct wire and voltage at the designated connector cavity.

CONTENTS

PCM

IMPORTANT PRELIMINARY CHECKS

BEFORE USING THIS SECTION

SYMPTOM

VISUAL/PHYSICAL CHECK

INTERMITTENTS

HARD START

PRELIMINARY CHECKS

SENSORS

IGNITION SYSTEM

FUEL SYSTEM

ADDITIONAL CHECKS

SURGES AND/OR CHUGGLES

PRELIMINARY CHECKS

SENSOR CHECKS

IGNITION SYSTEM CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

LACK OF POWER, SLUGGISH OR SPONGY

PRELIMINARY CHECKS

SENSOR CHECKS

ENGINE MECHANICAL CHECKS

IGNITION SYSTEM CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

DETONATION/SPARK KNOCK

PRELIMINARY CHECKS

IGNITION SYSTEM CHECKS

ENGINE MECHANICAL CHECKS

COOLING SYSTEM CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

HESITATION, SAG, STUMBLE

PRELIMINARY CHECKS

SENSOR CHECKS

IGNITION SYSTEM CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

CUTS OUT, MISSES

PRELIMINARY CHECKS

IGNITION SYSTEM CHECKS

ENGINE MECHANICAL CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

ROUGH, UNSTABLE, OR INCORRECT IDLE,

STALLING

PRELIMINARY CHECKS

ENGINE MECHANICAL CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

POOR FUEL ECONOMY

PRELIMINARY CHECKS

IGNITION SYSTEM CHECKS

COOLING SYSTEM CHECKS

ENGINE MECHANICAL CHECKS

ADDITIONAL CHECKS

FUEL SYSTEM CHECKS

BACKFIRE

PRELIMINARY CHECKS

IGNITION SYSTEM CHECKS

ENGINE MECHANICAL CHECKS

FUEL SYSTEM CHECKS

EXCESSIVE EXHAUST EMISSIONS OR ODOURS

PRELIMINARY CHECKS

IGNITION SYSTEM CHECKS

COOLING SYSTEM CHECKS

FUEL SYSTEM CHECKS

ADDITIONAL CHECKS

DIESELING, RUN-ON

PRELIMINARY CHECKS

FUEL SYSTEM CHECKS

IGNITION SYSTEM CHECKS

RICH/LEAN SYMPTOM CHART

CIRCUIT DESCRIPTION

TEST DESCRIPTION

DIAGNOSTIC AIDS

RICH/LEAN SYMPTOM CHART

AUTOMATIC TRANSMISSION SYMPTOM TABLES

OIL PRESSURE HIGH OR LOW

HARSH SHIFTS / INACCURATE SHIFT

POINTS

1ST GEAR RANGE ONLY – NO UPSHIFTS

SLIPS IN 1ST GEAR

SLIPPING OR ROUGH 1–2 SHIFT

NO 2-3 SHIFT OR 2-3 SHIFT SLIPS, ROUGH

OR HUNTING

2ND/3RD GEARS ONLY OR 1ST/4TH GEARS

ONLY

THIRD GEAR ONLY

3-2 FLARE OR TIE-UP

NO 3-4 SHIFT, SLIPS OR ROUGH 3-4 SHIFT

NO REVERSE OR SLIPS IN REVERSE

NO PART THROTTLE OR DELAYED

DOWNSHIFTS

HARSH GARAGE SHIFT

NO OVERRUN BRAKING - MANUAL 3-2 - 1

NO TCC APPLY

TORQUE CONVERTER CLUTCH SHUDDER

NO TCC RELEASE

DRIVES IN NEUTRAL

2ND GEAR START (DRIVE RANGE)

NO PARK

RATCHETING NOISE

FLUID OUT THE VENT

VIBRATION IN REVERSE AND WHINING

NOISE IN PARK

NO DRIVE IN ALL RANGES

NO DRIVE IN DRIVE RANGE

FRONT OIL LEAK

DELAY IN DRIVE AND REVERSE

PCM CONNECTOR SYMPTOM TABLES

TESTING GROUNDS

BASICS

GROUND CIRCUITS

PARALLEL GROUNDS

CHECKING GROUNDS

SOLID STATE CIRCUIT VOLTAGE DROP

SPECIFICATIONS

GROUND CREDIBILITY CHECK

CIRCUIT DESCRIPTION

TEST DESCRIPTION

DIAGNOSTIC AIDS

CORRECTING PROBLEMS IN GROUND

CIRCUITS

PCM

Since the PCM can have a failure which may affect only one circuit, following the Diagnostic Procedures in this

section will determine which circuit has a problem and where it is.

If a diagnostic T able indicates that the PCM connections or PCM is the cause of a problem, and the PCM is

replaced, but does not correct the problem, one of the following may be the reason:

• There is a problem with the PCM terminal connections. The diagnostic Table will say "PCM connections or

PCM." The terminals may have to be removed from the connector in order to check them properly.

• The PCM is not correct for the application. The incorrect PCM may cause a malfunction and may or may not set

a code.

• The problem is intermittent. This means that the problem is not present at the time the system is being

checked. In this c as e, ref er to the "Symptoms" Tables and m ake a carefu l phys ical inspec tion of all com ponents

of the system involved.

• Shorted solenoid, relay coil, or harness. Solenoids and relays are turned "ON" and "OFF" by the PCM, using

internal electronic switches called "Drivers." Each "driver" is part of a group of four (called "Quad drivers").

Failure of one driver may cause other drivers in the set to m alfunction. Solenoid and relay coil resis tance must

measure more than 20 ohms, in most cases. Less resistance may cause early failure of the PCM "driver."

Before r eplacing a PCM, be sure to c heck the c oil resistance of all solenoids and re lays controlled by the PCM.

See PCM wiring diagram for the solenoid(s) and relay(s) and the coil terminal identification.

• The replacement PCM may be faulty. After the PCM is replaced, the system should be rechecked for proper

operation. If the diagnostic Table again indicates the PCM is the problem, substitute a known good PCM.

Although this is an extremely rare condition, it could happen.

Figure 6C1-2B-1 – V6 Engine – Powertrain Wiring Harness to Engine Assembly Ground Locations.

Legend

1. Engine Ground Terminal.

2. Nut. 3. Engine Ground Terminal.

4. Bolt.

IMPORTANT P RELIMINARY CHECKS

BEFORE USING THIS SECTION:

Before using this Symptoms Section you should have performed the "On Board Diagnostic System Check" as

detailed in Section 6C1-2A DIAGNOSTIC TABLES and determined that:

1. The "Check Powertrain" Malfunction Indicator Lamp (MIL) is operating correctly.

2. There are no diagnostic trouble codes stored.

3. There is a diagnostic trouble code stored in the PCM memory and the "Check Powertrain” MIL is not activated.

4. The diagnostic table for the diagnostic trouble code indicates that the trouble is intermittent.

5. You are familiar with the Powertrain wiring harness to engine assembly ground locations, illustrated in Figure

6C1-2B-1 and as described in the various "SYMPTOM TABLES" in this Section.

SYMPTOM:

Verify the customer complaint, and locate the correct symptom in the table of contents. Check all the items

indicated under that symptom.

If the “ENGINE CRANKS BUT W ILL NOT RUN”, refer to Table A 3.1 in Sect ion 6C1-2A DIAGNOSTIC T ABLES –

V6 ENGINE.

VISUAL/PHYSICAL CHECK:

Several of the symptom procedures call for a “Careful Visual/Physical Check”. The importance of this step cannot

be stressed too strongly, as it can lead to the correction of a problem without further check s, saving valuable time.

This check should include the checking of:

• Service records for any recent repairs that may indicate a related problem, or the current need for scheduled

maintenance.

• PCM sensors for being in their proper location.

• PCM ground circuits ter minate at 2 separ ate eyelet terminals . On a V6 engine, thes e attac h to the engine at two

separate locations : the rear of the lef t cylinder head, and on the by-pass tube and drive belt tensioner attaching

stud, below the generator (refer Figure 6C1-2B-1). They must be clean and tight. Check for ground terminals

that m ay be loose under the retaining nuts/bolts, or for term inals that m ay have been left off after engine repair.

Any repair of the wire to terminal connection must include soldering with resin core solder. (NEVER use acid

core solder for any wiring repairs.)

• Vacuum hoses for splits, kinks, and proper connections. Check thoroughly for any type of leak or restriction.

• Air leaks at throttle body mounting area and intake manifold sealing surfaces.

• Ignition wires for cracking, hardness, proper routing and carbon tracking.

• Wiring for proper connections, pinches and cuts.

• Check for any non genuine Holden's options or accessories that may have been fitted to the vehicle that may

cause or exaggerate the problem.

INTERMITTENTS

DEFINITION: Problem may or may not activate the Check Powertrain Malfunction Indicator Lam p (MIL) or store a

DTC. DO NOT use the Diagnostic Trouble Code (DTC) Tables for intermittent problems. When using the DTC

Tables, the fault must be present to locate the problem. If a fault is intermittent, use of diagnostic trouble code

tables may result in replacement of good parts.

• Most inter mittent problem s are caused by faulty electrical connections or wiring. Perform car eful visual/physical

check as described at the start of this Section - "IMPORTANT PRELIMINARY CHECKS".

CHECK FOR:

• Poor mating of the connector halves or terminals not fully seated in the connector body (backed out).

• Improperly formed or damaged terminals. All connector terminals in the problem circuit should be carefully

reformed or replaced to ensure proper contact tension.

• Poor terminal to wire connection. This requires removing the terminal from the connector body to check as

outlined in service operations.

• PCM ground circuit terminals being loose at the engine. On a V6 engine these attach to the engine at two

separate locations : the rear of the lef t cylinder head, and on the by-pass tube and drive belt tensioner attaching

stud, below the generator, refer Figure 6C1-2B-1.

• If a visual/physical check does not find the cause of the problem, the car can be driven with a voltmeter

connected to a suspected circuit. Tech 2 can also be used to help detect intermittent conditions. An abnormal

voltage, or Tech 2 reading, when the problem occurs, indicates the problem may be in that circuit. If the wiring

and connectors check OK, and a diagnostic trouble code was stored for a circuit having a sensor, except for

DTCs P0132 or P0152 and P0131 or P0151, substitute a known good sensor and recheck.

• Loss of diagnostic code memory. To check, disconnect TP sensor and idle engine until the Check Powertrain

Malfunction MIL activates. DT C P0122 should be stored, and k ept in memory when ignition is turned "OFF." If

not, the PCM is faulty.

• With the V6 engine management system, an intermittent Check Powertrain MIL with no stored diagnostic

trouble code may be caused by:

– Ignition coil shorted to ground and arcing at spark plug wires or plugs.

– Intermittent short to + 12 volts on 0 – 5 volt input, circuits 410 (ECT sensor), 492 (MAF sensor), 411 (TP

sensor), and 5089 (IAT sensor).

• Check for an electrical system interference caused by a defective relay, PCM driven solenoid, or switch. They

can cause a sharp electrical surge. Normally, the problem will occur when the faulty component is operated.

• Check for improper installation of non-factory installed electrical options such as lights, 2 way radios, etc.

• EST wires should be routed away from spark plug wires, ignition wires, ignition module assembly and

generator. The wire from PCM to ignition should have a good connection.

• Check f or an open diode, acr os s A/C c ompres s or c lutch and for other open diodes ( ref er to the wiring diagrams

with TABLE A-11.1 or TABLE A-11.2 in Section 6C1-2A DIAGNOSTIC TABLES.

• If problem has not been found, refer to the proper symptom and perform all checks listed there.

HARD START

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

immediately dies.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

• Make sure the driver is using the correct starting procedure. Do not depress accelerator pedal during cranking.

• Work through TABLE A-3.1 ENGINE CRANKS BUT WILL NOT RUN in Section 6C1-2A DIAGNOSTIC

TABLES. Although this table may not exactly describe the problem, most all of the causes of a "no start" can

also cause a "hard start".

• Time or distance travelled since a normal engine tune-up has been performed, refer to time/distance intervals

specified in the MY 2003 VY and V2 Series Owner’s Handbook.

• PCM ground circuit terminals being loose at the engine. On a V6 engine these attach to the engine at two

separate locations : the rear of the lef t cylinder head, and on the by-pass tube and drive belt tensioner attaching

stud, below the generator, refer Figure 6C1-2B-1.

SENSORS:

CHECK:

• Engine Coolant Temperature (ECT) sensor using Tech 2, compare coolant temperature with ambient

temperature on cold engine.

If the coolant temperature reading is 5° C greater than or less than ambient air temperature on a cold engine,

check resistance in coolant sensor circuit or sensor itself. Compare ECT resistance value to the "Diagnostic

Aids" table on DTC P0117 table in Section 6C1-2A DIAGNOSTIC TABLES, in this Section.

• MAF sensor for a shifted sensor calibration, refer TABLE A-6.1 MAF SENSOR OUTPUT CHECK in Section

6C1-2A DIAGNOSTIC TABLES.

• TP Sensor for binding or a high TP sensor voltage with the throttle closed.

IGNITION SYSTEM:

CHECK:

• Spark plug leads being misrouted at the coils or at the spark plugs.

• For proper ignition voltage output with spark tester, Tool No. 7230 (also released as ST-125).

• Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, incorrect gap, burned electrodes, or

heavy deposits. Repair or replace as necessary.

• Bare or shorted wires.

FUEL SYSTEM:

CHECK:

• Fuel pump relay operation; pump should turn "ON" for 2 seconds when ignition is turned "ON." Use

TABLE A-4.1 for Engine.

• Fuel pressure, refer to TABLE A-4.3 in Section 6C1-2A DIAGNOSTIC TABLES.

• Contaminated fuel or incorrect fuel.

• If the problem occurs worse with hotter temperatures, check for leaking injectors, refer

Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

NOTE: A faulty in-tank f uel pum p check valve will allow the fuel in the lines to drain back to the tank after engine is

stopped. To check for this condition, perf orm fuel system diagnosis, refer Tab le A-4.3 FUEL DEL IVERY SYSTEM

in Section 6C1-2A DIAGNOSTIC TABLES.

ADDITIONAL CHECKS:

CHECK:

• Exhaust back pressure, refer Table A-13 RESTRICTED EXHAUST CHECK in Section 6C1-2A DIAGNOSTIC

TABLES, in this Section.

• IAC Operation, refer to Table A-7.1 IDLE AIR CONTROL (IAC) SYSTEM in Section 6C1-2A DIAGNOSTIC

TABLES.

• Basic engine problem. Camshaft timing chain for being stripped or slipped, causing valve timing to be retarded.

• Compression. Remove relays ‘X4’ (engine control – EFI) and ‘X16’ (fuel pump) from the underhood electrical

centre, before performing test.

• Service Techlines for update information.

SURGES AND/OR CHUGGLES

DEFINITION: Engine power variation under steady throttle or cruise, feels like the vehicle speeds up and slows

down with no change in the accelerator pedal.

PRELIMINARY CHECKS:

• Perform the careful visual checks as described at the start of this Section - "IMPORTANT PRELIMINARY

CHECKS".

• Make sure driver understands transmission torque converter clutch as explained in the Owner’s Handbook.

• Time or distance travelled since normal engine tune-up has been performed. Refer to time/distance intervals

specified in the MY 2003 VY and V2 Series Owner’s Handbook.

SENSOR CHECKS:

• Oxygen Sensor (HO2S). The Oxygen Sensor (HO2S) should respond quickly to different throttle positions. If

either one does not, chec k eac h Ox ygen Sensor (HO2S) f or silic on or other c ontam ination fr om fuel, or the us e

of improper RTV sealant.

The sensor may have a white, powdery coating and result in a high but false signal voltage (rich exhaust

indication). The PCM will then reduce the amount of fuel delivered to the engine, causing a severe driveability

problem. Also, look for coolant additive contamination or cracking. Also check the LTFT values with Tech 2.

• MAF sensor for proper operation, refer Table A-6.1 MAF SENSOR OUTPUT CHECK in Section 6C1-2A

DIAGNOSTIC TABLES.

IGNITION SYSTEM CHECKS:

• For proper ignition voltage output using spark tester, Tool No. 7230 (also released as ST-125).

• Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or

heavy deposits. Repair or replace as necessary. Also, check spark plug wires.

• Ignition secondary coil or wiring shorting to ground.

FUEL SYSTEM CHECKS:

• Contaminated or incorrect fuel.

NOTE: To determine if the condition is caused by a rich or lean system, the vehicle should be driven at the

speed of the c omplaint. Monitoring Long T erm Fuel Trim (LT FT ) and Short Ter m F uel Trim (ST FT) values with

Tech 2 will help to identify a problem.

Lean – Long Term F uel T r im near +25%. Refer to "Diagnos tic Aids " with DTCs P0131 or P0151 in Section 6C1-

2A DIAGNOSTIC TABLES.

Rich – Long T erm Fuel T rim near –22%. Ref er to "Diagnos tic Aids" with DT Cs P0132 or P0152 in Sec tion 6C1-

2A DIAGNOSTIC TABLES.

• Fuel pressure while condition exists, refer Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A

DIAGNOSTIC TABLES.

• In line fuel filter. Replace if dirty or plugged.

• Restricted fuel injectors. Perform an Injector Balance Test, using Tech 2 to check flow rate. Refer to

2.7 FUEL INJECTOR BALANCE TEST, in Section 6C1-2C FUNCTIONAL CHECKS – V6 ENGINE.

ADDITIONAL CHECKS:

• PCM ground circuits for being clean, tight and in their proper location.

• Vacuum lines for splits, kinks, leaks and proper connections.

• Generator output voltage. Repair if less than 9 or more than 16 volts.

• Speedometer reading with the speed on Tech 2 are equal.

• Service Bulletins for updates.

• Excessive exhaust back pressure, refer Table A-13 RESTRICTED EXHAUST CHECK in Section 6C1-2A

DIAGNOSTIC TABLES.

• TCC operation for proper operation.

LACK OF POWER, SLUGGISH, OR SPONGY

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

pushed down part way.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

• Compare customer's car to similar unit. Make sure the customer has an actual problem.

• Remove air filter and check air filter for dirt, or for being plugged. Replace as necessary.

• Tim e or distanc e travelled since norm al engine tune-up has been perform ed. Refer to time/distance intervals in

MY 2003 VY and V2 Series Owner’s Handbook.

SENSOR CHECKS:

• MAF sensor for proper operation, refer Table A-6.1 MAF SENSOR OUTPUT CHECK in Section 6C1-2A

DIAGNOSTIC TABLES.

ENGINE MECHANICAL CHECKS:

• Engine valve timing.

• Engine for correct or worn camshaft.

• Compression. Remove relays ‘X4’ (engine control – EFI) and ‘X16’ (fuel pump) from the underhood electrical

centre, before performing test.

IGNITION SYSTEM CHECKS:

• Secondary voltage using a shop oscilloscope or a spark tester ST-125 or 7230.

• For ignition misfire under heavy engine load. Check each spark plug lead for excessive resistance (or open

circuit), or for faulty or cracked spark plugs.

FUEL SYSTEM CHECKS:

• Restricted fuel filter, refer Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

• Fuel pressure, refer Table A -4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

• Contaminated fuel, refer Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

• Fuel Pump. Refer to Table A-4.1 FUEL PUMP ELECTRICAL CIRCUIT in Section 6C1-2A DIAGNOSTIC

TABLES.

ADDITIONAL CHECKS:

• PCM ground circuits for being clean, tight and in their proper locations.

• Generator output voltage. Repair if less than 9 or more than 16 volts.

• Exhaust system for possible re striction, refer Table A-13 REST RICTED EXHAUST CHECK in Section 6C1-2A

DIAGNOSTIC TABLES.

– Inspect exhaust system for damaged or collapsed pipes.

– Inspect muffler for heat distress or possible internal failure.

• Torque Converter Clutch (TCC) for proper operation (if the automatic transmission is fitted).

DETONATION/SPARK KNOCK

DEFINITION: A mild to severe ‘ping’, usually worse under acceleration. The engine makes sharp metallic knocks

that change with throttle opening.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

NOTE: If Tech 2 readings are normal (refer information with "On-Board Diagnostic System Check" in

Section 6C1-2A DIAGNOSTIC TABLES) and there are no engine mechanical faults, fill the fuel tank with a

premium unleaded fuel and re-evaluate vehicle performance.

IGNITION SYSTEM CHECKS:

• Spark plugs for proper heat range.

ENGINE MECHANICAL CHECKS:

• Combustion chambers for excessive carbon build up. Remove carbon with top engine cleaner and follow

instructions on can. If the problem re-occurs and top engine cleaner corrects it again, look for possible causes

of high oil consumption.

• For excessive oil in the combustion chamber – Valve stem oil seals leaking.

• Combustion chamber pressure by performing a compression test. Remove relays ‘X4’ (engine control – EFI)

and ‘X16’ (fuel pump) from the underhood electrical centre, before performing test.

• For incorrect basic engine parts such as camshaft, heads, pistons, etc.

COOLING SYSTEM CHECKS:

• Check for obvious overheating problems:

– Low engine coolant.

– Defective engine thermostat.

– Loose water pump drive belt.

– Restricted air flow to radiator, or restricted coolant flow through radiator.

– Inoperative electric cooling fan circuit, refer to Table A-12.1 ELECTRIC FAN CONTROL, in Section 6C1-

2A DIAGNOSTIC TABLES.

– Correct coolant solution should be a 50/50 mix of antifreeze coolant and water.

FUEL SYSTEM CHECKS:

• Fuel quality and proper octane rating.

NOTE: To determine if the condition is caused by a rich or lean system, the car should be driven at the speed of

the complaint. Monitoring Long Term Fuel Trim values with Tech 2 will help identify the problem.

Lean – Long Term F uel T r im near +25%. Refer to "Diagnos tic Aids " with DTCs P0131 or P0151 in Section 6C1-

2A DIAGNOSTIC TABLES.

Rich – Long T erm Fuel T rim near –22%. Ref er to "Diagnos tic Aids" with DT Cs P0132 or P0152 in Sec tion 6C1-

2A DIAGNOSTIC TABLES.

• Fuel pressure, refer to Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

ADDITIONAL CHECKS:

• Vacuum leaks.

• TCC operation (TCC applying too soon).

• Service Techlines for update information.

HESITATION, SAG, STUMBLE

DEFINITION: A momentary lack of response as the accelerator is pushed down. Can occur at all vehicle speeds.

Usually most sever e when fir st tr ying to mak e the c ar move, as f r om a s top sign. May cause engine to s tall if severe

enough.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

• Time or distance interval since normal engine tune-up has been performed. Refer to time/distance intervals

specified in Owner’s Handbook.

• Vacuum hoses for splits, kinks, and proper connections.

• For vacuum leaks at throttle body mounting and intake manifold.

SENSOR CHECKS:

• TP Sensor - Check TP Sensor for binding or sticking. Voltage should increase at a steady rate as throttle is

moved toward Wide Open Throttle (WOT), refer Table A-6.2 in Section 6C1-2A DIAGNOSTIC TABLES.

• MAF sensor, refer to Table A-6.1 MAF SENSOR OUTPUT CHECK in Section 6C1-2A DIAGNOSTIC TABLES.

• Engine coolant temperatur e s ensor res is tance. Ref er to DT C P0117 in Sec tion 6C1- 2A DIAG NOSTIC T ABLES,

for engine coolant temperature sensor temperature versus resistance table.

IGNITION SYSTEM CHECKS:

• Spark plugs for being fouled, or for there being faulty secondary wiring.

• Ignition system ground, circuit 453.

FUEL SYSTEM CHECKS:

• Fuel pressure, refer to Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

• Contaminated or incorrect fuel.

• Canister purge sy stem for proper operation.

• Fuel injectors. Perform injector balance test. Refer to 2.7 FUEL INJECT OR BALANCE T EST, in Section 6C1-

2C FUNCTIONAL CHECKS – V6 ENGINE.

ADDITIONAL CHECKS:

• Service Techlines for update information.

• Exhaust system back press ure, refer T able A-13 RESTRICT ED EXHAUST SYST EM T EST in Sec tion 6C1-2A

DIAGNOSTIC TABLES.

• Engine thermostat functioning correctly and proper heat range.

• Generator output voltage. Repair if less than 9 or more than 16 volts.

CUTS OUT, MISSES

DEFINITION: Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load

increases. The exhaust has a steady spitting sound at idle or under load.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

IGNITION SYSTEM CHECKS:

• If ignition system is suspected of causing a miss at idle or cutting out under load.

• If the previous checks did not find the problem, visually inspect ignition system for moisture, dust, cracks, burns,

etc. Spray plug wires with fine water mist to check for shorts.

• Check for a misfiring cylinder at idle by:

1. Start engine and perform a cylinder balance test, using Tech 2.

2. If there is an engine speed drop on all cylinders (equal to within 50 rpm), go to the

ROUGH, UNSTABLE, OR INCORRECT IDLE, STA LLING symptom, in this Section.

3. If there is no engine speed drop on one or more cylinders, or excessive variation in drop, check for spark on

the suspected c ylinder(s) with Spark Chec k ing Tool No. 7230 ( also released as ST -125). If no spark , check

plug lead for excessive resistance (or possibly ‘open'). If there is spark, remove spark plug(s) in those

cylinders and check for:

– Cracks – Wear.

– Improper Gap – Burned Electrodes.

– Heavy Deposits.

ENGINE MECHANICAL CHECKS:

• Compression. Perform compression check on questionable cylinder(s) found above. If compression is low,

repair as necessary. Remove relays ‘X4’ (engine control – EFI) and ‘X16’ (fuel pump) from the underhood

electrical centre, before performing test.

• Base engine. Remove rocker covers. Check for bent pushrods, worn rocker arms, broken valve springs, worn

camshaft lobes and valve timing, repair as necessary.

FUEL SYSTEM CHECKS:

• Fuel system – Blocked fuel filter, low pressure, refer Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-

2A DIAGNOSTIC TABLES.

• Contaminated or incorrect fuel.

• Performance of injector. If there is good spark and compression on all cylinders, check for restricted or non-

operating fuel injectors. To check for a non-operating injector, perform an Injector Balance test, using Tech 2,

or:

W ith the engine idling, check for c licking sound at each inj ector with a stethoscope or long screwdriver held on

the body of each injector. If any injector fails to make the clicking sound, disconnect the electrical connector,

and connect an injector node light tester such as Tool No. J34730-2C (also released as BT-8329), across the

harness connector terminals. If the test light blinks with the engine idling, replace the injector. If there is no

blinking light, check f or an "open" wire leading to that injector. Ref er to 3.1 ENGINE CRANKS BUT W ILL NOT

RUN, in Section 6C1-2A DIAGNOSTIC TABLES.

ADDITIONAL CHECKS:

• For EMI interference. A missing condition can be caused by Electromagnetic Interference (EMI) on the

reference circuit. EMI can usually be detected by monitoring engine RPM with Tech 2. A sudden increase in

engine speed with little change in actual engine RPM, is indicative that EMI is present. If the problem exists,

check routing of secondary wires and also check ground circuit.

• Intake and exhaust manifold passages for a casting flash.

ROUGH, UNSTABLE, OR INCORRECT IDLE , S TALLING

DEFINITION: Engine runs unevenly at idle. If bad enough, the vehicle may shake. Also, the idle may vary in RPM

(called "hunting"). Either condition may be bad enough to cause stalling. Engine idles at incorrect speed.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

• For vacuum leaks, they will cause an erratic idle.

• PCM grounds are clean, tight and in there correct location(s). Refer to PCM wiring diagrams.

• Idle Air Control (IAC) system for proper operation, refer Table A-7.1 IDLE AIR CONTROL (IAC) SYSTEM, in

Section 6C1-2A DIAGNOSTIC TABLES.

• For proper ignition voltage output using spark tester, Tool No. 7230 (also released as ST-125).

• Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or

heavy deposits.

ENGINE MECHANICAL CHECKS:

• Perform a cylinder compression check. Remove relays ‘X4’ (engine control – EFI) and ‘X16’ (fuel pump) from

the underhood electrical centre, before performing test.

• For correct camshaft valve lift and timing or weak valve springs.

FUEL SYSTEM CHECKS:

• For contaminated or incorrect fuel.

• For injectors that are restricted or not operating. Perform an Injector Balance Test, using Tech 2. Refer to

2.7 FUEL INJECTOR BALANCE TEST, in Section 6C1-2C FUNCTIONAL CHECKS – V6 ENGINE.

• For injectors leak ing, or incorrect fuel pressure, refer Table A-4.3 FUEL DELIVERY SYST EM in Section 6C1-

2A DIAGNOSTIC TABLES.

• Monitoring Long Term Fuel trim will help identify the cause of the problem . If the system is running lean (Long

Term Fuel Trim near +25%), refer to "Diagnostic Aids" with DTC P0131 or P0151 in Section 6C1-2A

DIAGNOST IC T ABLES in this Section. If the system is running rich (Long T erm Fuel Tr im near –22%) , refer to

"Diagnostic Aids" with DTC P0132 or P0152, in Section 6C1-2A DIAGNOSTIC TABLES.

• For fuel in pressure regulator hose. If fuel is present, replace regulator assembly.

• The Oxygen Sensors (HO2S) should respond quickly to different throttle positions, if they do not, check the

Oxygen Sensors (HO2S) for silicon contamination from fuel, or use of improper RTV sealant. The sensor will

have a white, powdery coating, and will result in a high but false signal voltage (rich exhaust indication). The

PCM will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem.

ADDITIONAL CHECKS:

• MAF sensor, refer to Table A-6.1 MAF SENSOR OUTPUT CHECK in Section 6C1-2A DIAGNOSTIC TABLES.

• Throttle linkage for sticking or binding.

• IAC operation, refer Table A-7.1 IDLE AIR CONTROL (IAC) SYSTEM in Section 6C1-2A DIAGNOSTIC

TABLES.

• A/C signal to PCM. Tech 2 should indicate A/C is being requested whenever A/C is selected and the blower

switch is "ON." If problem exists with A/C "ON," check A/C system operation Table A-11.1 A/C CONTROL

(Non OCC SYSTEM) or Table A-11.2 A/C CONTROL (With OCC SYSTEM) in Section 6C1-2A DIAGNOSTIC

TABLES.

• PCV valve for proper operation. Refer 2.1 POSITIVE CRANKCASE VENTILATION VALVE, in Section 6E1

EMISSION CONTROL V6 ENGINE, in the MY 2003 VY and V2 Series Service Information.

• Service Techlines for update information.

• For broken engine support mounts.

• Generator output voltage. Repair if less than 9 or more than 16 volts.

• Battery cables and ground straps should be clean and secure. Erratic voltage will cause IAC to change its

position resulting in poor idle quality.

POOR FUEL ECONOMY

DEFINITION: Fuel ec onomy, as m easur ed by an actual road test, is notic eably lower than expected. Also, economy

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

IMPORTANT: A m isfiring engine will have excessive unburned oxygen in the exhaust, and the "Closed-Loop" fuel

control system oxygen sensor will interpret a lean exhaust. The PCM will cause an increase in fuel injector pulse

width in attempts to overcome the lean exhaust indication.

PRELIMINARY CHECKS:

• Perform the careful visual checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

• Visually/physically check: Vacuum hoses for splits, kinks, and proper connections.

• Check owner's driving habits.

– Is A/C "ON" full time (Defroster mode "ON")?

– Are tyres at correct pressure?

– Are excessively heavy loads being carried?

– Is acceleration too much, too often?

• Check air cleaner element (filter) for dirty or being blocked.

• Check for correct size tyres. Oversize tyres will cause speedometer/odometer to be "slow," and indicated fuel

usage may increase.

IGNITION SYSTEM CHECKS:

• Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or

heavy deposits. Repair or replace as necessary.

COOLING SYSTEM CHECKS:

• Engine coolant level.

• Engine thermostat for faulty part (always open) or for wrong heat range.

ENGINE MECHANICAL CHECKS:

• Compression. Remove relays ‘X4’ (engine control – EFI) and ‘X16’ (fuel pump) from the underhood electrical

centre, before performing test.

ADDITIONAL CHECKS:

• TCC operation. Tech 2 should indicate an rpm drop, when the TCC is commanded "ON."

• For dragging brakes.

• For exhaust system restriction, refer to Table A-13 RESTRICTED EXHAUST CHECK in Section 6C1-2A

DIAGNOSTIC TABLES.

• For proper calibration of speedometer.

• Induction system and crankcase for air leaks.

• Exhaust system for air leaks before the oxygen sensor(s).

FUEL SYSTEM CHECKS:

• For leaking injectors or high fuel pressure or an external fuel leak.

• Long Term Fuel Trim values using Tech 2, for an abnormally high reading; i.e. greater than 10% (possibly

caused by engine misfiring).

BACKFIRE

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

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

IGNITION SYSTEM CHECKS:

• Proper ignition coil output voltage with spark tester, Tool No. 7230 (also released as ST-125).

• Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or

heavy deposits. Repair or replace as necessary.

• Spark plug wires for proper routing to avoid cross-fire and correct resistance.

ENGINE MECHANICAL CHECKS:

• Compression - Look for sticking or leaking valves. Remove relays ‘X4’ (engine control – EFI) and ‘X16’ (fuel

pump) from the underhood electrical centre, before performing test.

• Valve timing.

• Intake and exhaust manifold passages for a casting flash.

FUEL SYSTEM CHECKS:

• Perform "Fuel System Diagnosis Check", refer Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A

DIAGNOSTIC TABLES.

EXCESSIVE EXHAUST EMISSIONS OR ODOURS

DEFINITION: Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odours do not

necessarily indicate exce ssive emissions.

PRELIMINARY CHECKS

• Perform "On-Board Diagnostic System Check" in Section 6C1-2A DIAGNOSTIC TABLES.

IGNITION SYSTEM CHECKS:

• Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or

heavy deposits. Repair or replace as necessary.

COOLING SYSTEM CHECKS:

• If Tech 2 indicates a very high engine coolant temperature and the system is running lean, check:

– Engine coolant level.

– Engine thermostat for faulty part (always open) or for wrong heat range.

– Cooling fan operation.

FUEL SYSTEM CHECKS:

• For contaminated or incorrect fuel.

NOTE: If the system is running RICH (Long T erm F uel Tr im near –22%) - Refer to "Diagnostic Aids" with DT Cs

P0132 or P0152 in Section 6C1-2A DIAGNOSTIC TABLES. If the system is running LEAN (Long Term Fuel

Trim near +25%) - Refer to "Diagnostic Aids" with DTCs P0131 or P0151 in Section 6C1-2A DIAGNOSTIC

TABLES.

• For properly installed fuel tank cap.

• Fuel pressure, refer to Table A-4.3 FUEL DELIVERY SYSTEM in Section 6C1-2A DIAGNOSTIC TABLES.

• Canister for fuel loading.

ADDITIONAL CHECKS:

• For vacuum leaks.

• Burnt valves.

• For lead contamination of catalytic converter (look for the removal of the fuel filler neck restriction).

• Carbon build-up. Remove carbon with top engine cleaner. Follow instructions on can.

• For exhaust system restriction, refer to Table A-13 RESTRICTED EXHAUST CHECK in Section 6C1-2A

DIAGNOSTIC TABLES.

• PCV valve for being plugged or stuck, or fuel in the crankcase.

• Service Bulletins for updates.

DIESELING, RUN-ON

DEFINITION: Engine continues to run after ignition is turned "OFF," but runs very roughly.

PRELIMINARY CHECKS:

• Perform the careful visual/physical checks as described at the start of this Section;

"IMPORTANT PRELIMINARY CHECKS".

FUEL SYSTEM CHECKS:

• Injector s f or leak ing. Per form "F uel System Diagnosis Check ", ref er to T abl e A-4.3 F UEL DELI VERY SYST EM

in Section 6C1-2A DIAGNOSTIC TABLES.

IGNITION SYSTEM CHECKS:

• If engine runs smoothly, check ignition switch and adjustment.

RICH/LEAN SYMPTOM CHART

CIRCUIT DESCRIPTION:

The Rich/Lean Symptom Chart is an organised appr oach to identifying a driveability com plaint that may be caused

by an over rich or over lean operating condition. Under standing the Chart and us ing it corr ectly will reduce diagnostic

time and improve customer satisfaction. Start at the left side of the Chart and work to the right.

TEST DESCRIPTION:

NOTE: The number(s) below refer to the step number(s) on the diagnostic table.

1. This is a partial list of possible customer complaints and what the air/fuel mixture must be to cause such a

condition.

2. A lean exhaust m eans that there is a lot of ox ygen in the ex haust str eam . Lots of oxygen in the exhaust stream

means a low oxygen sensor signal voltage. Lean = lots of oxygen = low oxygen sensor signal voltage. A rich

exhaust means that there is some fuel and very little oxygen in the exhaust stream.

3. The oxygen sensor signal to the PCM determines what the PCM should do to compensate for the present

condition. Depending upon the severity of the problem , the PCM will compensate f or the condition by changing

the Short Term Fuel Trim and Long T erm Fuel Trim values either higher or lower. A short term fuel trim value

above 0% m eans the PCM will add m or e f uel to the engine, by increasing the injector pulsewidth, thus making a

lean engine run richer. A s hort term f uel trim value below 0% m eans the PCM will decr ease the am ount of fuel

to the engine, by decreasing the injector pulse width, thus making a rich engine run leaner.

4. This list represents areas where you should look to find the root cause of the customer complaint. Not every

cause of the symptom is listed here, however, the items listed provide a good general description of areas to

look at.

DIAGNOSTIC AIDS:

Driveability complaints may be caused by the PCM, system components or electrical faults, however, a basic engine

problem may also present a symptom sim ilar to an electr ical failure. Rem em ber to check the air cleaner and all the

basic engine components, there could be worn rings, worn camshaft lobes, collapsed lifters, misaligned timing

chain, vacuum leaks etc.

RICH/LEAN SYMPTOM CHART

VEHICLE OPERATION OXYGEN SENSOR

OPERA TION SHORT AND LONG TERM

FUEL TRIM OPERATION POSSIBLE CAUSES

CUSTOMER

DRIVEABILITY

COMPLAINT/SYMPTOM

EXHAUST

STREAM

STATUS

OXYGEN

SENSOR

VOLTAGE

LEAN Air/Fuel Mixture

High NOx Emis sions

Stumbles/Stalls

Surges

Poor Performance

High

Oxygen

Content

LEAN

EXHAUST

0 mV

+ 25 %

RICH COM MAND

ADD FUEL

LEAN Air/Fuel Mi xture

Short Term Fuel Trim and Long Term

Fuel Trim are numeric al ly i ncreasing

High (above 0%) possible DTC

P0131 or DTC P0151.

Oxygen Sensor voltage between 450

mV and 0 mV.

Cause: Fuel s ys t em not i n control.

Check For:

Poor PCM grounds.

Intak e manif ol d vacuum l eak.

Restricted fuel f i l ter.

Low fuel pressure.

Water c ontami nation in fuel .

Lean (restricted fl ow), fuel

injector(s).

16 to 1 Air/Fuel Mixture

Increas e I nj ector Pul se

Width

Oxygen Sensor being “Trick ed” Lean.

Cause: Too m uch air in exhaust

stream above oxygen sensor.

Cylinders not firing (misfire),

sending unburned air/ f uel mixture

into exhaust.

Cracked or leaking exhaust

manifold.

Oxygen sensor mount i ng i s loose,

dirty or has no sealing washer.

14.7:1 Air/Fuel Mixture 450 mV 0 % NO

CHANGE

RICH Air/Fuel Mixture

Short Term Fuel Trim and Long Term

Fuel Trim are numeric al ly decreasing

low (below 0%) possible DTC P 0132

or DTC P0152.

Oxygen Sensor voltage between 450

mV and 1,000 mV.

13 to 1 Air/Fuel Mixture

RICH Air/Fuel Mixture

High HC, CO Emis sions

Black Sm oke

Catalytic Converter Odour

Decrease I nj ector Pul se

Width

REMOVE FUEL

LEAN COMMAND

Cause: Fuel s ys t em not i n control.

Check For:

Restricted (dirt y) ai r f i l ter.

Leaking injector(s ).

High fuel pres sure.

Restricted fuel return line.

ECT tem perature value low.

Oxygen Sensor contaminated

(covered with foreign substance).

Engine oil contam i nated with fuel.

Canister purge continuous l y

purging.

– Fouled Spark Plugs RICH

EXHAUST 1, 000 mV –22% Oxygen Sensor being “Trick ed” Ri ch.

Cause: Not enough air i n exhaust .

Low

Oxygen

Content

Restricted exhaust s ys tem.

Oxygen Sensor ground, wire

open, or has a poor c onnection.

Oxygen Sensor poisoned

(impregnated with foreign

substance).

When using Tech 2 to observe S hort Term Fuel Tri m and Long Term Fuel Trim values, remem ber that, i f the syst em is i n control,

no action is required unless there is a driveabilit y symptom present.

AUTOMATIC TRANSMISSION SYMPTOM TABLES

OIL PRESSURE HIGH OR LOW

Checks Causes

Oil Pump Assembly • Pressure regulator valve stuck

• Pressure regulator valve spring

• Rotor guide omitted or disassembled

• Rotor cracked or broken

• Reverse boost valve or sleeve stuck, damaged or incorrectly assembled

• Orifice hole in pressure regulator valve plugged

• Sticking slide

• Pressure relief ball not seated or damaged

• Porosity in pump cover or body

• Wrong pump cover

• Pump faces not flat

• Excessive rotor clearance

Oil Filter • Intake pipe restricted by casting flash

• Cracks in filter body or intake pipe

• O-ring seal missing, cut or damaged

• Wrong grease used on rebuild

Valve Body • Manual valve scored or damaged

• Spacer plate or gaskets incorrect, misassembled or damaged

• Face not flat

• 2-3 Shift valve stuck

• Checkballs omitted or misassembled

Pressure Control Solenoid

Valve • Damage to pins

TFP Manual Valve Position

Switch • Contamination

• Damaged seals

Case • Case to valve body face not flat

HARSH SHIFTS/INACCURATE SHIFT POINTS

Checks Causes

Throttle Position Sensor • Open or shorted circuit

Vehicle Speed Sensor • Open or shorted circuit

TFP Manual Valve Position

Switch • Contamination

• Damaged seals

Trans Fluid Temperature

Sensor • Open or shorted circuit

Engine Coolant

Temperature Sensor • Open or shorted circuit

Pressure Control Solenoid

Valve • Damage to pins

• Contamination

Oil Pump Assembly • Stuck pressure regulator valve

• Sticking pump slide

Valve Body Assembly • Spacer plate or gaskets misassembled, damaged or incorrect

Case • Porous or damaged valve body pad

• 2-4 Servo Assembly:

– 2-4 accumulator porosity

– Damaged servo piston seals

– Apply pin damaged or improper length

• 2-4 Band Assembly:

– Burned

– Anchor pin not engaged

TP Sensor • Disconnected

• Damaged

Vehicle Speed Sensor • Disconnected

• Damaged

• Bolt not tightened

1ST GEAR RANGE ONLY - NO UPSHIFT

Checks Causes

Valve Body • The 1-2 Shift valve is sticking

• The spacer plate or gaskets are mispositioned or damaged

Case • The case to valve body face is damaged or is not flat

Shift Solenoid Valves • Stuck or damaged

• Faulty electrical connection

2-4 Servo Assembly • The apply passage in the case is restricted or blocked

• Nicks or burrs on the servo pin or on the pin bore in the case

• Fourth servo pistons installed backwards

2-4 Band Assembly • The 2-4 band is worn or damaged

• The band anchor pin is not engaged

Vehicle Speed Sensor • No signal.

SLIPS IN 1ST GEAR

Checks Causes

Forward Clutch Assembly • Clutch plates worn

• Porosity or damage in forward clutch piston

• Forward clutch piston inner and outer seals missing, cut or damaged

• Damaged forward clutch housing

• Forward clutch housing retainer and ball assembly not sealing or damaged

Forward Clutch

Accumulator • Piston seal missing, cut or damaged

• Piston out of its bore

• Porosity in the piston or valve body

• Stuck abuse valve

Forward Sprag Assembly • Forward sprag assembly not holding

Input Housing and Shaft

Assembly • Turbine shaft seals missing, cut or damaged

Valve Body • 1-2 Accumulator valve stuck

• Face not flat, damaged lands or interconnected passages

• Spacer plate or gaskets incorrect, mispositioned or damaged

Low Roller Clutch • Damage to lugs to inner ramps

• Rollers not free moving

• Inadequate spring tension

• Damage to inner splines

• Lube passage plugged

Torque Converter • Stator roller clutch not holding

1-2 Accumulator Assembly • Porosity in piston or 1-2 Accumulator cover and pin assembly

• Damaged ring grooves on piston

• Piston seal missing, cut or damaged

• Valve body to spacer plate gasket at 1-2 Accumulator cover, missing or damaged

• Leak between piston and pin

• Broken 1-2 Accumulator spring

Line Pressure • Refer to Oil Pressure High or Low

2-4 Servo Assembly • 4th Servo piston in backward

SLIPPING OR ROUGH 1-2 SHIFT

Checks Causes

Valve Body Assembly • 1-2 Shift valve train stuck

• Gaskets or spacer plate incorrect, mispositioned or damaged

• 1-2 Accumulator valve stuck

• Face not flat

2-4 Servo Assembly • Apply pin too long or too short

• 2nd servo apply piston seal missing, cut or damaged

• Restricted or missing oil passages

• Servo bore in case damaged

1-2 Accumulator • Porosity in 1-2 accumulator housing or piston

• Piston seal or groove damaged

• Nicks or burrs in 1-2 accumulator housing

• Missing or restricted oil passage

2-4 Band • Worn or mispositioned

Oil Pump Assembly or Case • Faces not flat

NO 2-3 SHIFT OR 2-3 SHIFT SLIPS, ROUGH OR HUNTING

Checks Causes

Torque Converter • Internal damage.

Valve Body Assembly • 2-3 Shift valve train stuck.

• Accumulator valve stuck.

• Gaskets or spacer plate incorrect, mispositioned or damaged.

2-4 Servo Assembly • 2nd apply servo piston seals missing, cut or damaged.

Input Housing Assembly • Clutch plates worn (3-4 or forward).

• Excessive clutch plate travel.

• Cut or damaged 3-4 or forward clutch seals.

• Porosity in input clutch housing or piston.

• 3-4 Piston checkball stuck, damaged or not seating.

• Restricted apply passages.

• Forward clutch piston retainer and ball assembly not seating.

• Sealing balls loose or missing.

Oil Pump Assembly • Stator shaft sleeve scored or off location.

Transmission Case • 3rd accumulator retainer and ball assembly not sealing.

2ND/3RD GEARS ONLY OR 1ST/4TH GEARS ONLY

Checks Causes

Shift Solenoid Valves • Sediment is in the valves.

• The electrical connection is faulty.

• Damaged seal.

THIRD GEAR ONLY

Checks Causes

DTC 81 • The electrical connection is faulty.

• Shorted or damaged.

3-2 FLARE OR TIE-UP

Checks Causes

3-2 Shift Solenoid • Shorted or damaged.

• Contamination.

• Damaged Seal.

NO 3-4 SHIFT, SLIPS OR ROUGH 3-4 SHIFT

Checks Causes

Oil Pump Assembly • Pump cover retainer and ball assembly omitted or damaged.

• Faces not flat.

Valve Body Assembly • Valves stuck:

– 2-3 Shift valve train.

– Accumulator valve.

– 1-2 Shift valve train.

– 3-2 Shift valve.

• Spacer plate or gasket incorrect, mispositioned or damaged.

2-4 Servo Assembly • Incorrect band apply pin.

• Missing or damaged servo seals.

• Porosity in piston, cover or case.

• Damaged piston seal grooves.

• Plugged or missing orifice cup plug.

Case • 3rd Accumulator retainer and ball assembly leaking.

• Porosity in 3-4 accumulator piston or bore.

• 3-4 Accumulator piston seal or seal grooves damaged.

• Plugged or missing orifice cup plug.

• Restricted oil passage.

Input Housing Assembly • Refer to Slipping 2-3 Shift

2-4 Band Assembly • Worn or Disassembled

NO REVERSE OR SLIPS IN REVERSE

Checks Causes

Input Housing Assembly • 3-4 Apply ring stuck in applied position.

• Forward clutch not releasing.

• Turbine shaft seals missing, cut or damaged.

Manual Valve Link • Disconnected.

Valve Body Assembly • 2-3 Shift valve stuck.

• Manual linkage not adjusted.

• Spacer plate and gaskets incorrect, mispositioned or damaged.

• Lo overrun valve stuck.

• Orificed cup plug restricted, missing or damaged.

Reverse Input Clutch

Assembly • Clutch plate worn.

• Reverse input housing and drum assembly cracked at weld.

• Clutch plate retaining ring out of groove.

• Return spring assembly retaining ring out of groove.

• Seals cut or damaged.

• Restricted apply passage.

• Porosity in piston.

• Belleville plate installed incorrectly.

• Excessive clutch plate travel.

• Oversized housing.

Lo and Reverse Clutch • Clutch plates worn.

• Porosity in piston.

• Seals damaged.

• Return spring assembly retaining ring mispositioned.

• Restricted apply passage.

NO PART THROTTLE OR DELAYED DOWNSHIFTS

Checks Causes

2-4 Servo Assembly • Servo cover retaining ring omitted or misassembled.

• 4th Apply piston damaged or misassembled.

• Servo inner housing damaged or misassembled.

Valve Body Assembly • 3-2 Downshift valve stuck.

• 4-3 Sequence valve body channel blocked.

HARSH GA RAGE SHIFT

Checks Causes

Valve Body Assembly • Orifice cup plug missing.

• Checkball missing.

NO OVERRUN BRAKING - MANUAL 3-2-1

Checks Causes

External Linkage • Not adjusted properly.

Valve Body Assembly • 4-3 Sequence valve stuck.

• Checkball mispositioned.

• Spacer plate and gaskets incorrect, damaged or mispositioned.

Input Clutch Assembly • Turbine shaft oil passages plugged or not drilled.

• Turbine shaft seal rings damaged.

• Turbine shaft sealing balls loose or missing.

• Porosity in forward or overrun clutch piston.

• Overrun piston seals cut or damaged.

• Overrun piston checkball not sealing.

NO TCC APPLY

Checks Causes

Electrical • 12 Volts not supplied to transmission.

• Outside electrical connector damaged.

• Inside electrical connector, wiring harness or solenoid damaged.

• Electrical short (pinched solenoid wire).

• Solenoid not grounded.

Converter • Internal damage.

Oil Pump Assembly • Converter clutch valve stuck or assembled backwards.

• Converter clutch valve retaining ring mispositioned.

• Pump to case gasket mispositioned.

• Orifice cup plug restricted or damaged.

• Solenoid O-ring seal cut or damaged.

• High or uneven bolt torque (pump body to cover).

Input Housing and Shaft • Turbine shaft O-ring seal cut or damaged.

• Turbine shaft retainer and ball assembly restricted or damaged.

TFP Manual Valve

Position Switch • Contamination.

• Damaged seals.

Valve Body Assembly • TCC signal valve stuck.

• Solenoid O-ring leaking.

Solenoid Screen • Blocked.

TCC Solenoid Valve • Valve stuck.

Engine Speed Sensor • Incorrect or no signal.

Engine Coolant

Temperature Sensor • Temperature reading too low or too high.

DTCs P0121, P0122,

P0123, P0740, P0753,

P1810, P1860

–

Transmission Fluid

Temperature Sensor • Temperature reading incorrect

TORQUE CONVERTER CLUTCH SHUDDER

Checks Causes

Electrical • 12 Volts not supplied to transmission.

• Powertrain harness connector to pass-thru connector damaged.

• Internal connector, wiring harness or solenoid damaged.

• Electrical short (pinched solenoid wire).

• Solenoid not grounded.

Converter • Internal damage.

Oil Pump Assembly • Converter clutch valve stuck or assembled backwards.

• Restricted oil passage.

Input Housing and Shaft • Turbine shaft O-ring seal cut or damaged.

• Turbine shaft retainer and ball assembly restricted or damaged.

Fluid Filter • Crack in filter body.

• Casting flash restricting filter neck.

• O-ring seal cut or damaged.

Miscellaneous • Low fluid pressure.

• Engine not tuned correctly.

Input Housing and Shaft

Assembly • Turbine shaft O-ring cut or damaged.

• Turbine shaft retainer and ball assembly restricted or damaged.

NO TCC RELEASE

Checks Causes

TCC Solenoid Valve • Internal ground.

• Clogged exhaust orifice.

Converter • Internal damage.

Valve Body Assembly • The converter clutch apply valve is stuck in the apply position.

Oil Pump Assembly • The converter clutch valve is stuck.

PCM • External ground.

DRIVES IN NEUTRAL

Checks Causes

Forward Clutch • The clutch does not release

Manual Valve Link • Disconnected

Case • The face is not flat

• Internal leakage exists

2ND GEAR START (DRIVE RANGE)

Checks Causes

Forward Clutch Sprag

Assembly • The sprag assembly is installed backwards.

NO PARK

Checks Causes

Parking Linkage • Actuator rod assembly bent or damaged.

• Actuator rod spring binding or improperly crimped.

• Actuator rod not attached to inside detent lever.

• Parking lock bracket damaged or not torqued properly.

• Inside detent lever not torqued properly.

• Parking pawl binding or damaged.

RATCHETING NOISE

Checks Causes

Parking Pawl • The parking pawl return spring is weak, damaged, or misassembled

FLUID OUT THE VENT

Checks Causes

Oil Pump • Chamber in pump body rotor pocket.

Miscellaneous • Fluid level – overfilled.

VIBRATION IN REVERSE AND WHINING NOISE IN PARK

Checks Causes

Oil Pump • Chamber in pump body rotor pocket.

Miscellaneous • Fluid level – overfilled.

NO DRIVE IN ALL RANGES

Checks Causes

Torque Converter • The converter to flex plate bolts are missing.

NO DRIVE IN DRIVE RANGE

Checks Causes

Torque Converter • The stator roller clutch is not holding.

• The converter to flex plate bolts are missing.

FRONT OIL LEAK

Checks Causes

Torque Converter • The welded seam is leaking.

• The converter hub is damaged.

Torque Converter Seal • The seal assembly is damaged.

• The garter spring is missing.

DELAY IN DRIVE AND REVERSE

Checks Causes

Torque Converter • Converter drainback

PCM CONNECTOR SYMPTOM TABLES

The following Powertrain Control Module (PCM) connector Symptoms Tables identifies the function of each pin of

the PCM connector, the c irc uit number, the wire colour , and the c avity of the com ponent to which the wire connects.

The left column in these table lists the PCM connector pins in ascending order. The tables may also be entered

from the r ight-m ost colum n, which lis ts poss ible symptom s that m ay be caused by a fault in each of the cir cuits. If a

problem in any of these circuits will cause a Diagnostic Trouble Code to be set, the DTC's are identified in the

second column from the right edge of the Table. (However, if a DTC has been s et, you should attem pt to diagnose

the condition using Section 6C1-2A DIAGNOSTIC TABLES - V6 ENGINE, before diagnosing by symptom.) The

expected normal voltage for each circuit is shown for two conditions. Check the voltage with the ignition "ON" but

the engine not running, and with the engine running. Both checks are required for accurate diagnosis. Reference

notes are made for some circuits. These notes state conditions that cause varying voltages or mention unique

characteristics of the circuit. To m easure the voltages, backprobe the PCM connector. W henever backprobing, be

careful not to damage the connector. Careless backprobing may damage the connector seal and/or terminal.

Damaged pins will provide incorrect readings and cause additional system problems.

PCM CONNECTOR A84 – X1

POWERTRAIN CONTROL MODULE CONNECTOR “A84 X1” SYMPTOMS TABLE

BROWN 24 PIN – ROW ‘A’

NORMAL VOLTAGES POSSIBLE SYMPTOMS

FROM FAULTY CIRCUIT

FUNCTION CKT

No. WIRE

COLOUR COMPONENT/

CONNECTOR CAVITY

IGN “ON” ENG RUN

DTCs

AFFECTED

A1 3-2 CONTROL

SOLENOID 898 GN/WH 3-2 CONTROL

SOLENOID,

TERMINAL X121-X2 ‘S’

12 * P0785 SOFT LANDING INTO

THIRD GEAR

STAY IN THIRD GEAR.

A2 2-3 SHIFT

SOLENOID ‘B’

CONTROL

1223 YE/BK 2-3 S HI FT SOLENOID ‘B ’

TERMINAL X121-X2 ‘B’ 12 * P0730

P0757

(9)

POSSIBLY THIRD GEAR

ONLY, NO TCC

OPERA TION, MAXIMUM

LINE PRESSURE.

A3 LPG ENABLE

(LPG Only) 2531 WH/ G N LPG TANK S MART UNIT 12 * P1642 LPG SYSTEM INOP

A4 NOT USED – – – – – – –

A5 SYSTEM

GROUND 450 BK/RD ENGINE GROUND * * NONE NO START IF A LL

GROUND CIRCUITS ARE

OPEN.

A6 NOT USED – – – – – – –

A7 MAF SENSOR

INPUT 492 BN/WH MASS AI R FLOW

SENSOR B 68

TERMINAL X1-A

4.8 4.2 P0101 RICH EXHAUST

A8 START RELAY

CONTROL 434 GY START RELAY R1

TERMINAL ‘86’ * * NONE NO START

A9 AIR

CONDITIONING

RELAY CONT ROL

459 L-GN/BK A/C RELAY R11

TERMINAL ‘2’ 12 (3) NONE ROUGH IDLE, NO AIR

CONDITIONING

A10 AIR

CONDITIONING

RELAY CONT ROL

428 GN/YE CANISTER PURGE

SOLENOID Y 123

TERMINAL X1-B

12 13 P0446 RICH EXHAUST

A11 TCC SOLENOID

PWM CONTROL 418 BN TCC SOLENOID

TERMINAL X121-X2 ‘U’ 12 13 P1860 NO TCC

A12 TCC ENABLE

SOLENOID

CONTROL

422 GY/RD TCC SOLENOID

TERMINAL X121-X2

‘T’12

12 13 P-740

(9) NO TCC AND NO

FOURTH GEAR IF IN

HOT MODE

(3) Less than 0.50 volt when A/C is commanded ON, 13 volts if commanded OFF

(9) Open/Grounded Circuit.

* Less than 0.50 Volts.

** Refer to Wiring Diagrams.

A84 V6 – X1

PCM CONNECTOR A84 – X1

POWERTRAIN CONTROL MODULE CONNECTOR “A84 X1” SYMPTOMS TABLE

BROWN 24 PIN – ROW ‘B’

NORMAL VOLTAGES POSSIBLE SYMPTOMS

FROM FAULTY CIRCUIT

FUNCTION CKT

No. WIRE

COLOUR COMPONENT/

CONNECTOR CAVITY

IGN “ON” ENG RUN

DTCs

AFFECTED

B1 1-2 SHIFT

SOLENOID ‘A’

CONTROL

1222 L-GN 1-2 SHIFT SOLE NOI D ‘ A ’

TERMINAL X121-X2 ‘A’ 12 * P0753

P0756

(9)

2ND and 3RD GEAR

ONLY or 1ST and 4TH

GEAR ONLY and

MAXIMUM L INE

PRESSURE.

B2 NOT USED – – – – – – –

B3 EST OUTPUT 423 WH IGNITION MODULE A 40

TERMINAL ‘X1-A’ 0 2.0 P1351

P1361 HARD T O START,

STALL.

B4 BYPASS

CONTROL 424 TN/BK IGNITION MODULE A40

TERMINAL ‘X1-B’ 0 4.7 P1351

P1361 POOR PERFORMANCE

B5 SYSTEM

GROUND 2753 BK ENGINE SENSOR

GROUND * * NONE NO START IF A LL

GROUND CIRCUITS ARE

OPEN.

B6 CAMSHAFT

POSITION

SENSOR S IGNAL

630 BK IGNITION MODULE N40

TERMINAL ‘X1-F’ 7.0 6.1 P0341

P0342 SEQUENTIAL FUEL

INJECTION MAY BE OUT

OF SEQUENCE

B7 CRANKSHAFT

18X SIGNAL 647 L-BU/BK IGNITION MODULE N40

TERMINAL ‘X1-C’ 5 2.7 or 3.0 P0374

(9) NO HIGH RESOLUTI ON

EST

B8 TORQUE

REQUEST 463 OG ABS/TCS MODULE A37

TERMINAL ‘X1-13’ 10 – 12 10 – 12 – –

B9 CRANKSHAFT

REFERENCE

HIGH

430 PU IGNI TI ON MODULE N40

TERMINAL ‘X1-D’ 4.8 2.3 P1372 NO START

B10 CRANKSHAFT

REFERENCE

LOW

453 BK/RD IGNITION MODULE N40

TERMINAL ‘X1-L’ * * NONE POOR PERFORMANCE,

INTERMITTENT MIL,

NO DTC

B11 TORQUE

ACHIEVED 464 BK/WH ABS/TCS MODULE A37

TERMINAL ‘X1-27’ 0.9 3.6 – –

B12 ENGINE

COOLING FAN

HIGH SPEED

CONTROL

335 BU/WH ENGINE COOLI NG FA N

2 RELAY ‘ R5’ ,

TERMINAL ‘86’

12 (7) NONE HIGH ENGINE

TEMPERATURE,

OVERHEATING

(7) Less than 0.50 volt when A/C is commanded ON, 13 volts if commanded OFF.

(9) Open or grounded circuit.

* Less than 0.50 Volts.

** Refer to Wiring Diagrams.

A84 V6 – X1

PCM CONNECTOR A84 – X2

POWERTRAIN CONTROL MODULE CONNECTOR “A84 X2” SYMPTOMS TABLE

BROWN 24 PIN – ROW ‘C’

NORMAL VOLTAGES POSSIBLE SYMPTOMS

FROM FAULTY CIRCUIT

FUNCTION CKT

No. WIRE

COLOUR COMPONENT/

CONNECTOR CAVITY

IGN “ON” ENG RUN

DTCs

AFFECTED

C1 VEHICLE SPEED

OUTPUT TO

SPEEDOMETER

5197 PU/WH INSTRUMENT

CONNECTOR ‘P 3’

TERMINAL ‘X1-5’

(1) (1) NONE INOPERATIVE

SPEEDOMETER

C2 IAC

‘1’ COIL: LOW 1748 L-BU/BK IDLE AIR CONTROL

VALVE ‘Y20’ TERMINAL

‘X1-B’

NOT USEAB LE P0506 S T ALLING, ROUGH,

UNSTABLE OR

INCORRECT I DLE

C3 IAC

‘2’ COIL: HIGH 1749 L-BU I DLE AIR CONTROL

VALVE ‘Y20’ TERMINAL

‘X1-D’

NOT USEAB LE P0506 S T ALLING, ROUGH,

UNSTABLE OR

INCORRECT I DLE

C4 IAC

‘2’ COIL: LOW 444 L-GN/BK IDLE A IR CONTROL

VALVE ‘Y20’ TERMINAL

‘X1-C’

NOT USEA B LE STA LLI NG, ROUGH,

UNSTABLE OR

INCORRECT I DLE

C5 IAC

‘1’ COIL: HIGH 1747 L-GN/WH I DLE AIR CONTROL

VALVE ‘Y20’ TERMINAL

‘X1-A’

NOT USEA B LE STA LLI NG, ROUGH,

UNSTABLE OR

INCORRECT I DLE

C6 ECT/TP SENSOR

GROUND 2752 BK/ Y E ECT ‘B39’ TERMINAL

‘X1-B’, TP SENSOR

‘B82’ TERMINA L ‘X1-B’

* * P0117

P0118

P0123

POOR PERFORMANCE,

HARD START,

HESITATION

C7 TP SENSOR

SIGNAL 411 BU TP SENSOR ‘B82’

TERMINAL ‘X1-C’ (5) (5) P0122

P0123 POOR PERFORMANCE,

HIGH IDLE

C8 EGR PINTLE

POSITION 1456 L-GN EGR VALVE Y56

TERMINAL ‘X1-C’ 0.7 0.7 P0405 ROUGH IDLE , STA LLI NG

C9 RH OXYGEN

SENSOR S IGNAL 1666 GY RH OXYGEN SENS OR

‘B70 R’

TERMINAL ‘X1-A’

450 mV (4) P0131

P0132

P0134 (9)

NO “CLOSED LOOP”

OPERATION

C10 LH KNOCK

SENSOR S IGNAL 496 BU LH KNOCK SENSOR

‘B65’ TERMINAL X1-A’ 1. 3 mV

A/C 25.6 mV

A/C P0327 ENGINE KNOCK

C11 RH KNOCK

SENSOR 1876 L-BU RH KNOCK SENSOR

‘B65’ TERMINAL X1-A’ 1. 3 mV

A/C 25.6 mV

A/C P0332 ENGINE KNOCK

C12 BATTERY

VOLTAGE 740 OG/BK FUSE F29 12 13 NONE NO START

C13 PRIMARY SERIAL

DATA 800 RD/BK DLC ‘ X40’TERMINA L ‘ 9’

BCM ‘A15’ TERMINAL

‘X2-5’

3 – 5 3 – 5 P1255 NO SERIA L DATA, NO

CRANK

C14 INJECTOR

VOLTAGE

MONITOR LINE

639 RD FUSE F34 12 13 P0200

C15 TP SENSOR

REFERENCE

VOLTAGE

416 GY TP SENSOR B82

TERM. ‘X1-A’, MAP

SENSOR B67 TERM.

‘X1-A’, A/C PRESSURE

SENSOR ‘B18’

TERMINAL ‘X1-B’

5 5 P0122

P0123 ROUGH IDLE

C16 EGR REFERENCE

VOLTAGE 5047 PU/WH EGR ’Y56’ TERMINAL

‘X1-B’ 5 5 P0405 ENGINE DETONATION

ROUGH IDLE.

(1) Varies f rom 0.10 V ol ts to about 13 Volt s, depending on pos i tion of drive wheels when vehicle i s m ovi ng.

(4) Voltage s houl d vary between 100 mV and 1000 mV.

(1) 0.25 – 1.25 Volts at i dl e to above 4.0 Volts at Wide Open Throttl e.

(9) Open/Grounded Circuit.

* Less than 0.50 Volts.

** Refer to Wi ri ng Di agrams.

A84 V6 – X2

PCM CONNECTOR A84 – X2

POWERTRAIN CONTROL MODULE CONNECTOR “A84 X2” SYMPTOMS TABLE

BROWN 24 PIN – ROW ‘D’

NORMAL VOLTAGES POSSIBLE SYMPTOMS

FROM FAULTY CIRCUIT

FUNCTION CKT

No. WIRE

COLOUR COMPONENT/

CONNECTOR CAVITY IGN “ON” ENG RUN

DTCs

AFFECTED

D1 VEHICLE SPEED

SENSOR S IGNAL

LOW

1230 BU/WH

(AUTO.

and

MANUAL)

VEHICLE SPEED

SENSOR,

TERMINAL X121-X1 A

* * P0502

P0503 SPEEDOMETER

INOPERATIVE –

MAXIMUM L INE

PRESSURE.

D2 VEHICLE SPEED

SENSOR S IGNAL

HIGH

1231 TN

(AUTO.

and

MANUAL)

VEHICLE SPEED

SENSOR,

TERMINAL X121-X1 B

* * P0502

P0503 SPEEDOMETER

INOPERATIVE –

MAXIMUM L INE

PRESSURE, SECOND

GEAR ONLY.

D3 LH OXYGEN

SENSOR

GROUND

1664 BU/BK LH OXYGEN SENSOR

‘B70 L’,

TERMINAL ‘X1-B’

* * P0151

P0152 NO ‘CLOSED LOOP’

OPERATION (8).

D4 LH OXYGEN

SENSOR S IGNAL 1665 PU LH OXYGEN SENSOR

‘B70 L’,

TERMINAL ‘X1-A’

450 mV (4) P0151

P0152

P0154

NO “CLOSED LOOP”

OPERATION (9).

D5 RH OXYGEN

SENSOR

GROUND

1667 GY/ B K RH OXYGEN SENSOR

‘B70 R’,

TERMINAL ‘X1-B’

* * P0131

P0132 NO ‘CLOSED LOOP’

OPERATION (8).

D6 TFT, EGR,

GROUND TO

ENGINE GROUND

‘GP5 – X119’

450 BK/RD TFT SENSOR ‘X121-X2

M’, EGR VALVE ‘Y56’

TERMINAL ‘X1-A’

* * P0112

P0405

P0530

P0713

SLIGHT HIGH IDLE,

TCC APPLY EARLY

D7 INTAKE AIR

TEMPERATURE

SENSOR S IGNAL

5089 BN IAT SENSO R ‘ B 64’

TERMINAL ‘X1-A’ 1.0 (6) 1.0 (6) P0111

P0112

P0113

NONE

D8 MAP SENSOR 432 L-GN MAP SENSOR ‘B 67’

TERMINAL ‘X1-B’ 5 5 P0107

P0108 ABNORMAL AUTO

TRANS SHIFTS AT HIGH

ALTITUDES

D9 NOT USED – – – – – – –

D10 A/C PRESSURE

SENSOR S IGNAL 380 GN/BK A/C PRESSURE

SENSOR ‘B18’

TERMINAL ‘X1-C’

1 – 2 1 – 2 P0530 A/C INOPERAT IVE

D11 ENGINE

COOLANT

TEMPERATURE

SENSOR S IGNAL

410 YE ECT SENSOR ‘B18’,

TERMINAL ‘X1-A’ 1.9

(6) 1.9

(6) P0117

P0118

P1116

HARD STA RT , LONG

CRANK TIME

D12 BATTERY

VOLTAGE FEED 740 OG/BK FUSE F29 12 13 NONE NO START I F ‘ C12’ IS

ALSO OPEN.

D13 TRANS FLUID

TEMPERATURE

SENSOR S IGNAL

1227 BK/YE TRANSMISSION PASS-

THROUGH

CONNECTOR X121-X2,

TFT TERMINAL ‘A’

1.8

(6) 1.8

(6) P0712

P0713 MAXIMU M L INE

PRESSURE, TCC IN

SECOND, T HIRD, AND

FOURTH GEA RS

D14 NOT USED – – – – – – –

D15 NOT USED – – – – – – –

D16 IGNI TION FEED 300 OG FUSE F10 12 13 NONE NO ‘CHECK

POWE RT RAIN MIL’, NO

START.

(4) Voltage should vary between 100 mV to 1,000 mV.

(6) Varies with Temperature.

(8) Open

(6) Open/Grounded Circuit.

(7) Grounded Circuit

* Less than 0.50 Volts.

** Refer to Wiring Diagrams.

A84 V6 – X2

PCM CONNECTOR A84 – X3

POWERTRAIN CONTROL MODULE CONNECTOR “A84 X3” SYMPTOMS TABLE

TAN 24 PIN – ROW ‘E’

NORMAL VOLTAGES POSSIBLE SYMPTOMS

FROM FAULTY CIRCUIT

FUNCTION CKT

No. WIRE

COLOUR COMPONENT/

CONNECTOR CAVITY

IGN “ON” ENG RUN

DTCs

AFFECTED

E1 NOT USED – – – – – – –

E2 FUEL INJECTOR

#2 CONTROL 1745 GN FUEL INJECTOR #2 12 13 NONE ROUGH IDLE, HARD

START

E3 NOT USED – – – – – – –

E4 FUEL INJECTOR

#1 CONTROL 1744 BU FUE L I NJECTOR #1 12 13 NONE ROUGH IDLE, HA RD

START

E5 FUEL INJECTOR

#5 CONTROL 845 B N/ YE FUE L INJECTOR #5 12 13 NONE ROUGH IDLE, HARD

START

E6 FUEL INJECTOR

#6 CONTROL 846 YE FUEL INJECTOR # 12 13 NONE ROUGH IDLE , HARD

START

E7 SYSTEM

GROUND 450 BK/RD ENGINE GROUND AT

GP5-X119 * * NONE NO START IF ALL

GROUND CIRCUITS ARE

OPEN

E8 NOT USED – – – – – – –

E9 PRESSURE

CONTROL

SOLENOID HIGH

1228 RD TRANSMISSION PASS-

THRU CONNECTOR

X121-X2 TERMINAL ‘C’

* 1.3 P0748 MAXIMUM LINE

PRESSURE, HARD

SHIFT (8)

E10 FUEL PUMP

RELAY CONT ROL 465 GN/WH FUEL PUMP RELA Y R16

TERMINAL ‘2’ (4) (2) 13 NONE HARD TO START , LONG

CRANK TIME

E11 NOT USED – – – – – – –

E12 EGR CONTROL

(PWM) 1676 PU EGR VALVE Y56

TERMINAL ‘X1-E’ 0.0% 0.0% P0400

P0405 ROUGH IDLE, SPARK

KNOCK. (9)

E13 PRESSURE

CONTROL

SOLENOID LOW

1229 GY/BU TRANSMISSION PASS-

THRU CONNECTOR

X121-X2 TERMINAL ‘D’

* 6.8 P0748 (9) MAXI MUM LINE

PRESSURE - HARD

SHIFT

E14 NOT USED – – – – – – –

E15 NOT USED – – – – – – –

E16 FUEL CONTROL

VALVE (LPG Only) 5623 B K /BU FUEL CONTROL VALVE

SOLENOID, ‘ Y143’ 12 5 – 7

(1) P1643 LPG SYSTEM INOP

(1) Only when operating in the LPG Mode.

(2) 12 Volts for the First Two Seconds after Ignition is Turned ON without Cranking.

(4) 12 Volts when Fuel Pump is Running.

(6) Varies with Temperature.

(8) Open

(9) Open/Grounded Circuit.

* Less than 0.50 Volts.

** Refer to Wiring Diagrams.

A84 V6 – X3

PCM CONNECTOR A84 – X3

POWERTRAIN CONTROL MODULE CONNECTOR “A84 X3” SYMPTOMS TABLE

TAN 24 PIN – ROW ‘F’

NORMAL VOLTAGES POSSIBLE SYMPTOMS

FROM FAULTY CIRCUIT

FUNCTION CKT

No. WIRE

COLOUR COMPONENT/

CONNECTOR CAVITY

IGN “ON” ENG RUN

DTCs

AFFECTED

F1 FUEL INJECTOR

#3 CONTROL 1746 PU FUE L I NJECTOR #3 12 13 NONE ROUGH IDLE, HA RD

START

F2 FUEL INJECTOR

#4 CONTROL 844 BN/WH FUEL INJECTOR #4 12 13 NONE ROUGH IDLE, HARD

START

F3 PRNDL “A ” 771 BU/WH PRNDL SWITCH S187

TERMINAL ‘X2-A’ * * NONE IMPROPER GEAR

INDICA T E D ON

INSTRUMENT PANEL (9)

F4 FUEL MODE

SW ITCH (LPG

Only)

5606 L-GN FUE L MODE SWIT CH

S118 * * NONE LPG SYS T E M INOP

F5 NOT USED – – – – – – –

F6 PRNDL “P ” 776 WH PRNDL SWITCH S187

TERMINAL ‘X2-P’ * * NONE IMPROPER GEAR

INDICA T E D ON

INSTRUMENT PANEL (9)

F7 SYSTEM

GROUND 450 BK/RD ENGINE GROUND AT

GP5-X119 * * NONE NO START IF ALL

GROUND CIRCUITS ARE

OPEN.

F8 PRNDL “B ” 772 Y E PRNDL SWITCH S187

TERMINAL ‘X2-P’ * * NONE IMPROPER GEAR

INDICA T E D ON

INSTRUMENT PANEL (9)

F9 PRNDL “C” 773 GY PRNDL SWIT CH S 187

TERMINAL ‘X2-P’ * * NONE IMPROPER GEAR

INDICA T E D ON

INSTRUMENT PANEL (9)

F10 NOT USED – – – – – – –

F11 RANGE SIGNAL

“A” 1224 BN/YE TRANSMISSION PASS-

THRU CONNECTOR

X121-X2 TERMINAL ‘N’

12 13 P1810 MAXIMUM LINE

PRESSURE, NO

FOURTH GEAR IF IN

HOT MODE, NO TCC

OPERATION (8)

F12 RANGE SIGNAL

“B” 1225 YE TRANSMISSION PASS-

THRU CONNECTOR

X121-X2 TERMINAL ‘R’

0 0 P1810

(8) NONE

F13 RANGE SIGNAL

“C” 1226 GY TRANSMISSION PASS-

THRU CONNECTOR

X121-X2 TERMINAL ‘P’

12 13 P1810 MAXIMUM LINE

PRESSURE, NO

FOURTH GEAR IF IN

HOT MODE, NO TCC

OPERATION (8)

F14 POWER/

ECONOMY

SWITCH

553 BU POWER/ECONOMY

SWI T CH S22

TERMINAL ‘X1-3’

12 13 NO POWER S HI FT

PATTERN

F15 OIL PRESSURE

SWITCH INPUT 231 BU/RD OIL PRESSURE

SW ITCH, S87 * 13 NONE OIL LIGHT ON

F16 IGNITION FEED

(LPG Only) 300 OG FUSE F10 12 13 NONE NO CHECK

POWERTRAIN MIL,

NO START

(8) Open Circuit.

(9) Open/Grounded Circuit.

* Less than 0.50 Volts.

** Refer to Wiring Diagrams.

A84 V6 – X3

TESTING GROUNDS

Unusual displays in the instrument, lamps that are dim or flash unexpectedly, stop lamps that come on when the

indicators are used, are all classic symptoms of ground problems.

This section discusses the importance of good ground circuits and starts by explaining some basic theory. Then, the

diagnosis of a solid-state circuit ground condition is detailed, to help show how to correct a problem, should it occur.

BASICS

For a circuit to operate properly, three things are

needed:

a. A good power supply to components;

b. Good components and,

c. Sound ground circuits.

Circuits are complete systems; current must flow

from beginning to end as designed, not hinder ed by

unexpected resistance anywhere in the circuit.

While some Technicians realise that the power

supply to a circuit must be free of unwanted

resistance, they can have difficulty in visualising

why a ground cir cuit mus t also be fr ee of unwanted

resistance.

For current to flow, the circuit must be complete; it

must pass through and out of a component like

water flowing thr ough a bathtub. With a f ree f lowing

tub (no plug inserted), the water can flow out as

freely as it flows in. In electrical term s , current m ust

also enter and leave components freely, if they are

to perform as they are designed.

Figure 6C1-2B-2

Sensitive, solid-s tate systems have their own ground points; high c urrent devic es (e.g. m otor s) do not ground at the

same location. High current devices can cause voltage spikes (sudden changes in voltage) when turned “ON” or

“OFF.” To prevent these spikes from affecting sensitive solid-state circuits, two different types of different ground

location s ystem s are used. An exam ple is the use of a dedic ated wir e to connect an isolated ground junc tion block

to the battery negative terminal. This wire reduces the effect of spikes on sensitive circuits at the ground junction

block.

Solid-state circuits are particularly sensitive to poor circuit continuity because, in most cases, they use low current

flow. T his Sec tion on ground c ir cuits , c oncer ns itse lf with one solid-s tate device; the PCM. However, the information

included here can also be applied to all solid-state ground circuits.

Severe restrictions (i.e. resistance) in the ground circuit can cause resets and intermittent codes to set, in solid-state

systems. The PCM operates devic es such as fuel injec tors, idle air control (IAC) , etc., and rec eives inputs from low

voltage sensors, such as the mass air flow sensor (MAF), manifold absolute pressure (MAP) (where fitted),

crankshaft speed/position (CKP). These input and output devices need good circuitry for correct operation.

Remember that, when maladjusted or defective sensors cause values to shift, they are usually accompanied by

driveability problems. If there is excessive resistance in the ground circuit, then the result will be the sam e; shifted

sensor outputs with corresponding driveability conditions. These conditions may not be severe enough to set

diagnostic trouble codes, but they will reduce vehicle efficiency and performance and may be noticed by the

customer.

Sensor circuit ground sensitivity – an example. Looking at the Throttle Position (TP) sensor circuit will provide an

example of how a little resistance in the ground circuit can cause problems. Figure 6C1-2B-3 shows a throttle

position sensor (1) first with a good ground circuit (‘A’) and then with a poor connection (‘B’) in the ground circuit.

Refer to this illustration, as you proceed through the text that follows:

First, the throttle position sensor consists of a resistor and a wiper and, one terminal of the resistor is connected to a

supply voltage (5 V) , while the other is connec ted to ground. As the wiper m oves across the resistor, the voltage of

the wiper terminal progressively changes, with a change in the throttle position. If the wiper is near the supply

voltage end of the resistor, the wiper output will approach the supply voltage (over 4.5 volts at wide open throttle).

As the wiper m oves toward the grounded end of the resistor , the voltage of the wiper output decreases to near zero

(about 0.5 volts for the closed throttle in this example). Note though, that the actual closed and wide open throttle

voltage specifications may vary for different engines. Also, the sensor output should never be greater than reference

supply voltage or less than 0.20 volts. (The PCM would set a DTC, should this situation occur.)

Figure 6C1-2B-3

In the f irst exam ple with a good gr ound circuit (‘A’), the T P sensor (1) is s hown with the wiper in the closed throttle

position. T he total voltage acros s the r esistor in the TP s ensor is 5 volts . The voltage drop f rom the resistor s ource

voltage terminal to the wiper is 4.5 volts. The voltage drop from the wiper to the resistor ground side is 0.5 volts. The

wiper output is 0.5 volts – a good value for this example of a closed throttle.

Now, look at the sensor with the bad signal caused by resistance in the ground circuit. The throttle position stays the

sam e but the sens or output voltage changes . In this exam ple the increas ed resistanc e causes an additional voltage

drop of 0.5 volts. The voltage drop from the wiper to ground is now 1.0 volt (0.5 + 0.5 = 1.0). Because the source

voltage is a constant 5 volts, the voltage drop from the source voltage input to the wiper can now be only 4 volts (5.0

– 1.0 = 4.0). The PCM now receives 1.0 Volt from the TP sensor. This is not a good value (in this example) of a

closed throttle.

Now you can see why good grounds are needed and how sensitive some circuits can be.

GROUND CIRCUITS

How do you know which wires are ground wires, which connectors they go through, and whether they are connected

to a ground junction or the body?

Refer to Section 12P, WIRING DIAGRAMS for reference whenever you are diagnosing any electrical condition,

including grounds. The individual circuits show the power and ground circuits for components in specific systems.

If you suspec t s everal c ircuits are being af f ected by a poor or a back -f eed to ground, look at the circ uits to s ee how

the systems might interact. If they have any common ground wires, that is where you should start diagnosis.

Back -feeding is when current, s eeking ground, f eeds back through inac tive circuits (the r everse direction of normal

current flow) to find a path to ground. This can only happen when the active circuit (needing a ground) shares a

disconnected or poor ground with an inactive circuit and the voltage supply side of the inactive circuit feeds other

components with good grounds.

PARALLEL GROUNDS

Some solid-state components use redundant ground circuits. That is, they have more than one wire connecting to

ground. The PCM has more than one ground circuit wire. There are several reasons for redundant grounds.

The PCM has many low-current circuits, but the current from all these circuits (when they are active) adds up to a

larger current. Higher current loads are managed more easily with several regular size wires, rather than with one

large diameter wire.

Basic circuit theory shows that the effective

resistance of parallel resistors is less than any of

the individual resistors. The simple example shown,

proves this to be true and holds for even the small

resistance’s in wires.

It follows that parallel wires provide the lowest

resistance. Because of them, in many solid-state

systems a problem with one of the ground wires

would not affect the circuit; the redundant wires

could handle the current load. For other solid-state

systems the loss of even one redundant ground

may affect operation, but the remaining ground

wire(s) may allow the vehicle to be driven.

Figure 6C1-2B-4

An example that can be difficult to locate, follows:

Symptom: A vehicle has driveability problems. However, whenever Tech 2 is hooked up and the vehicle tested,

none of the complaint sy mptoms are displayed.

Cause: T he PCM grounds ar e not providing a good ground, henc e the resulting driveability c ondition. When T ech 2

is connected to the vehicle, a good ground path is provided for the PCM through the Data Link Connector (DLC).

The DLC uses a diff erent gr ound than the PCM. Always test for driveability sym ptom s befor e hooking up T ech 2. If

they disappear when Tech 2 is hooked up, check the ground circuit for continuity.

The severity of the sym ptom (s) is propor tional to the s everity of the problem in the gr ound circuit. A com plete open

in the circuit has the most severe effect. Use the severity of the symptom(s) as an indication of the extent of the

open in the ground circuit.

CHECKING GROUNDS

Once you determine that the cause of the vehicle symptom(s) m ay be caused by a bad ground, it is time to check

for poor ground with one more tool: a high-impedance multimeter set to DC Volts.

The best way to check for poor ground connections in low-current solid-state circuits is to check the voltage drop.

To do this you need a high-impedance digital m ultimeter ( DMM) rated at a minim um of 10 megaohm s (10,000,000

ohms ) per volt. Any DMM with less impedanc e than this c an aff ec t the circuit being tested and also give an incorrec t

reading.

Start by checking the entire suspect ground circuit. With the DMM set on the 2 Volt DC scale, connect the black

negative lead to the battery negative (ground) term inal. (If you are using an auto-ranging m eter, sim ply set it to the

DC volts setting.)

Connect the red positive lead of the DMM to the ground terminal of the component to be tested. With the circuit

activated, check the voltage drop in the circuit. If the voltage reading is within specific ations, look f or a c ause other

than a poor ground at this component.

If the voltage drop reading is too high, proceed by isolating the cause of the high voltage drop. Move the positive

lead to the next connection in the ground circuit, working closer to the source voltage. (Keep the negative lead

connected to the battery negative terminal.) Be sure to check both sides of each in-line connector and both the

eyelet and the stud or screw at ground points. Repeat this process through the ground path until the voltmeter

reading is within specifications. The high resistance causing the ground problem is located between where you

obtained a good reading and the last high reading.

When a circuit uses redundant grounds be sure to check all the ground circuits for excessive voltage drop.

SOLID-STATE CIRCUIT VOLTAGE DROP SPECIFICATIONS

There ar e two ac c eptable maximum voltage dr ops for s olid-s tate c irc uits. If you are measur ing the voltage drop of a

circuit that will pass through a solid-state component before going to ground (such as the ECT sensor circuit

between the ECT sensor and the PCM), measured voltage cannot be higher than 0.060 volts (60 millivolts).

If you are measuring the voltage drop of a solid-state ground circuit anywhere in the ground path at or after the

solid-state component (such as the PCM ground circuit from the PCM to the battery), the maximum allowable

measured voltage is 0.020 volts (20 millivolts). If you measure a voltage above specifications, repair the ground

circuit.

ACCEPTABLE VOLTAGE DROP READINGS

BETWEEN SE NS OR AND PCM 0.060 V (60 mV)

BETWEEN PCM AND BATTERY

NEGATIV E TERMINAL 0.020 V (20 mV)

Checking the voltage drop in a solid-state sensor circuit.

Example ’A’: Look again at the Engine Coolant T emper ature ( ECT ) s ensor c irc uit. With the voltmeter negative lead

connected to the negative battery terminal and the ignition ON, check the voltages at various points between the

ECT sensor B39, term inal “X 1-B” and PCM A84, term inal “X2-C6”. A voltage reading of 0.060 volts or les s with the

meter positive lead at the ECT sens or, terminal “X 1-B” indicates that the entire ground circuit fr om the ECT sensor

to the battery is continuous and sufficiently low in resistance. A voltage reading of 0.060 volts at the “splice” or the

PCM connector “X2-C6” pin would also be within specifications.

Figure 6C1-2B-5 Testing Voltage Drop Before and After the PCM

Legend

A Voltage Drop Testing Before the PCM

1. Voltage Reading to be 0.060 Volt, Maximum B Voltage Drop Testing After the PCM

2. Voltage Reading to be 0.020 Volt, Maximum

Exam ple ‘B’: When voltage m easur em ents are m ade in the gr ound circuit af ter the PCM, the s pecific ation changes.

A voltage reading of 0.020 volts (20 millivolts) or less is within specification. If voltage is not within specifications

check the different c onnector s to f ind where the exc ess voltage is . Be s ure to c hec k both s ides of in-line c onnec tors

and both the eyelet and the stud at ground points.

GROUND CREDIBILITY CHECK

Figure 6C1-2B-6 – Intake Air Temperature Sensor

CIRCUIT DESCRIPTION:

The ground c r edibility check can be either us ed at the beginning of all diagnos tic pr oc edures or it can be used when

no diagnostic trouble codes are set, but a symptom still exists.

TEST DESCRIPTION:

NOTE: Number(s) below refer to step number(s) on the diagnostic table.

2. To properly test the voltage drop of the Powertrain Control Module (PCM) system ground, a load must be

present on the circuit.

Using Tech 2, select CANISTER PURGE. By turning “ON” the Purge solenoid, this will cause a sufficient

current draw on the system for testing.

2. Check connectors in ground circuit to find where the excessive voltage is. Make sure to check both sides of in-

line connectors.

DIAGNOSTIC AIDS:

Because the PCM operates on such small current even a minor corrosion problem will cause problems with the

system. Make sure the grounds are clean and tight. Remember a good ground is about 25% of the total system

circuit. Normally you will check the wiring for; power, continuity, the load, but rarely check the ground. Powertrain

control module system grounds are very important to proper operation.

B64 X119_GP5 AND GP6

Figure 6C1-2B-7

GROUND CREDIBILITY CHECK

STEP ACTION VALUE YES NO

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

performed? Go to Step 2. Go to

OBD System

Check.

2. 1. Ignition "OFF"

2. Disconnect IAT sensor connector.

3. Using Digital Multimeter (DMM) set to DC voltage

scale, connect negative lead to negative battery cable

at battery and connect positive lead to the black wire

at the IAT sensor connector.

4. Ignition "ON"

5. Using Tec h 2, sele ct CANISTER PURGE.

6. Turn "ON'" Canister Purge.

Is voltage measured less than value shown.

0.060 volts

(60

Millivolts)

No problem

found, continue

with symptom

diagnosis.

Go to Step 3

3. 1. Remove and thoroughly clean the PCM ground

terminals and connection.

2. Reassemble the PCM Ground terminals.

Is action complete?

Verify Repair –

CORRECTING PROBLEMS IN GROUND CIRCUITS

Once a high resistance condition in a ground circuit has been located, you must determine the actual cause.

If the problem is at a connector, check for bent, corroded, or loose connector terminals. Terminals m ust have a

slight drag when disassembled/assembled. If they slide apart/together without resistance, they will not provide a

good connection.

If the prob lem is at a st ud , bolt, or sheet metal screw, check for corrosion, paint, or loose connections. Paint can

be a very good insulator; good conductors, not insulators are needed for electrical connections.

Corrosion, paint, and other contaminants should be removed using a wire brush and/or emery cloth.

When assem bling ground wire eyelet's to ground points, be sur e an external type star w asher is placed below the

wire eyelet(s). If the system is marginal, you can also place a s tar washer between the nut or the sheet- metal s cr ew

and the top wire eyelet. Tighten the fastener to specification, making sure the star washer digs through any paint

into the mounting surface. Star washers also lock the fastener in place, preventing it from loosening.

All fasteners should be tightened so that the fastener head presses the ground wire eyelet or star washer to the

mounting surface and stops. Repair any stripped ground fasteners.

IMPORTANT: Do not over-tighten sheet-metal screws. Over-tightening can enlarge the hole and create a bad

ground. If the sheet-metal is enlarged, the screw will continue to turn: drill a new correctly sized hole for the screw.