check engine ISUZU AXIOM 2002 Service Repair Manual

6E±530
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom

StepActionValue(s)Ye sNo
1DEFINITION:
Momentary lack of response as the accelerator is
pushed down. Can occur at any vehicle speed. Usually
most pronounced when first trying to make the vehicle
move, as from a stop sign. May cause the engine to stall
if severe enough.
Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Was the ªElectric Throttle Control (ETC) System
Checkº performed?
ÐGo to Step 3
Go to ETC
System
Check
31. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
ÐVerify repairGo to Step 4
4Was a visual/physical check performed?
ÐGo to Step 5
Go to Visual/
Physical
Check
51. Check the fuel control heated oxygen sensors
(HO2S, B1S1 and B2S1). The fuel control heated
oxygen sensors (HO2S) should respond quickly to
different throttle positions. If they don't, check them
for silicon or other contaminants from fuel or use of
improper RTV sealant. The sensors may have a
white powdery coating.
Silicon contamination causes a high but false
HO2S signal voltage (rich exhaust indication).
The PCM will then reduce the amount of fuel
delivered to the engine, causing a severe
driveability problem. For more information, refer
to
Powertrain Control Module (PCM) and Sensors.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 6
61. Check the fuel pressure. Refer to Fuel System
Pressure Test.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 7
7Observe the TP 1, 2 angle display on the Tech 2 while
slowly increasing accelerator pedal depression.
Does the TP angle display steadily increase from 8 ~
10% at closed throttle to 90 ~ 92% at WOT?
ÐGo to Step 8Go to Step 9
8Monitor the long term fuel trim on the Tech 2.
Is the long term fuel trim significantly in the negative
range (rich condition)?
ÐGo to Step 9Go to Step 10
91. Check items that can cause the engine to run rich.
Refer to
Diagnostic Aids in DTC P0172 Diagnostic
Support
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11

6E±531
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom

 
StepNo Ye s Value(s) Action
101. Check items that can cause the engine to run lean.
Refer to
Diagnostic Aids in DTC P0171 Diagnostic
Support
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electronic Ignition
System
for the procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
121. Check for a loose ignition coil ground and ION
Sensing module circuit.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 13
131. Check the ignition coils for cracks or carbon
tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 14
141. Remove spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 15
151. Check the PCM grounds for clearness, tightness
and proper routing. Refer to the PCM wiring
diagrams in Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 16
161. Check the MAF sensor connections.
2. If a problem is found, replace the faulty terminals as
necessary. Refer to
Electrical Diagnosis for wiring
repair procedures.
Was a problem found?
ÐVerify repairGo to Step 17

6E±532
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom

 
StepNo Ye s Value(s) Action
171. Visually/physically check vacuum hoses for splits,
kinks, and proper connections and routing as
shown on the ªVehicle Emission Control
Informationº label.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 18
181. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

Visual/physical inspection

Tech 2 data

Freeze Frame data/Failure Records butter

All electrical connections within a suspected
circuit and/or system
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Contact
Technical
Assistance

6E±533
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Bank 1 Restricted Exhaust System Check

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Remove the Bank 1 HO2S 2.
2. Install the Exhaust Backpressure Tester
(BT-8515-V or equivalent) in place of the Bank 1
HO2S 2.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 3Go to Step 4
3Repair the restriction in the exhaust system after the
catalytic converter.
Possible faults include:

Collapsed pipe

Heat distress

Internal muffler failure
Is the action complete?
ÐVerify repairÐ
41. Install the Bank 1 HO2S 2.
2. Install the Exhaust Backpressure Tester in place of
Bank 1 HO2S 1.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 5
No trouble
found. If a
driveability
symptom
exists, refer
to symptom
charts
5Repair the restriction in the catalytic converter.
Is the action complete?
ÐVerify repairÐ
NOTE: DTCs will be set by running the vehicle to normal
operating temperature after a cold start with the O2
sensor disconnected. After performing these tests, use
the Tech 2 to erase the DTCs that were set by the lack of
O2 sensor activity.

6E±534
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Bank 2 Restricted Exhaust System Check

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Remove the Bank 2 HO2S 2.
2. Install the Exhaust Backpressure Tester
(BT-8515-V or equivalent) in place of the Bank 2
HO2S 2.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 3Go to Step 4
3Repair the restriction in the exhaust system after the
catalytic converter.
Possible faults include:

Collapsed pipe

Heat distress

Internal muffler failure
Is the action complete?
ÐVerify repairÐ
41. Install the Bank 2 HO2S 2.
2. Install the Exhaust Back pressure Tester in place of
Bank 1 HO2S 1.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 5
No trouble
found. If a
driveability
symptom
exists, refer
to symptom
charts
5Repair the restriction in the catalytic converter.
Is the action complete?
ÐVerify repairÐ
NOTE: DTCs will be set by running the vehicle to normal
operating temperature after a cold start with the O2
sensor disconnected. After performing these tests, use
the Tech 2 to erase the DTCs that were set by the lack of
O2 sensor activity.

6E±535
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Default Matrix Table
Service Procedure Default Strategy
A referral strategy has been established to assist the
technician with additional information when the cause of
the failure cannot be determined. If no problem is found
after performing diagnostics, then refer to the default
matrix table for further diagnostic information.
Default Matrix Table
Strategy Based Diagnostic Charts
Initial DiagnosisDefault Section(s)
On-Board Diagnostic (OBD) System
CheckVehicle does not enter diagnostics.Chassis Electrical
On-Board Diagnostic (OBD) System
CheckVehicle enters diagnostics and
communicates with the Tech 2. MIL is
ªONº in diagnostics. Engine does not
start and run.Ignition System Check
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no PCM
codes set. Customer complains of
vibration.Ð
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no PCM
codes set. Customer complains of
harsh or soft shift, poor performance,
delayed or no engagement into drive
or reverse, transmission fluid leak,
transmission noise or vibration, or
improper TCC operation.Automatic Transmission
PCM Power and Ground CheckOn-Board Diagnostic (OBD) System
Check.Chassis Electrical
PCM Power and Ground CheckOn-Board Diagnostic (OBD) System
Check. PCM power and ground
circuits OK. Data link voltage
incorrect.Chassis Electrical
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no PCM
codes set. Customer complains of
harsh or soft shift, poor performance,
delayed or no engagement into drive
or reverse, transmission fluid leak,
transmission noise or vibration, or
improper TCC operation.Automatic Transmission
SymptomsInitial DiagnosisDefault Section(s)
Intermittents1. On-board Diagnostic (OBD)
system check.
2. Careful visual/physical
inspections.Chassis Electrical
Hard Starts1. OBD system check.
2. ETC system check.
3. Sensors (ECT, MAP, MAF, TP) ;
MAP output chart.
4. Fuel system electrical test, fuel
system diagnosis.
5. Ignition system.Engine Mechanical, Ignition
System Check, Exhaust System
Diagnosis

6E±536
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Symptoms Default Section(s)Initial Diagnosis
Surges and/or Chuggles1. OBD system check.
2. ETC system check.
3. Heated oxygen sensors.
4. Fuel system diagnosis.
5. Ignition system.Calibration ID/Service Bulletins,
Ignition System Check,
Generator Output, Exhaust
System Diagnosis, 4L30-E
System Test
Lack of Power, Sluggish or Spongy1. OBD system check.
2. ETC system check.
3. Fuel system diagnosis.
4. Ignition system.
5. EGR operation.
6. EGR system check.Refer to Exhaust System in
Engine Exhaust, TCC Operation,
Calibration ID/Service Bulletins
Detonation/Spark Knock1. OBD system check.
2. Transmission range switch.
3. EGR operation.
4. EGR system check.
5. TCC operation.
6. Fuel system diagnosis.
7. Ignition system.
8. ION sensing module check.TCC operation, Cooling System,
Ignition System Check,
Calibration ID/Service Bulletins
Rough, Unstable, or Incorrect Idle,
Stalling1. OBD system check.
2. ETC system check.
3. Fuel injector and fuel injector
balance test.
4. EVAP emission canister purge
valve check.
5. Ignition system.
6. EGR operation.MAP Output Check, Throttle
Linkage, EGR System Check,
A/C Clutch Control Circuit
Diagnosis, Crankcase Ventilation
System, Calibration ID/Service
Bulletins, Generator Output
Voltage (refer to
Chassis
Electrical
), Exhaust Diagnosis
Poor Fuel Economy1. OBD system check.
2. Careful visual/physical inspection.
3. Ignition system.
4. Cooling system.TCC Operation, Exhaust System
(refer to
Engine Exhaust)
Hesitation, Sag, Stumble1. OBD system check.
2. ETC system check.
3. TP.
4. MAP output check.
5. Fuel system diagnosis.
6. Fuel injector and fuel injector
balance test.
7. EVAP emission canister purge
valve.
8. Ignition system.EGR Operation, EGR System
Check, Generator Output
Voltage (refer to
Chassis
Electrical
), Calibration ID/Service
Bulletins, Ignition System Check
Cuts Out, Misses1. OBD system check.
2. Cylinder balance test.
3. ETC system check.Ignition System Check
Engine Cranks But Will Not Run1. OBD system check.Fuel System Electrical
Diagnosis, Fuel System
Diagnosis, Fuel Injector and Fuel
Injector Balance Test.

6E±537
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Symptoms Default Section(s)Initial Diagnosis
Excessive Exhaust Emissions or
Odors1. OBD system check.
2. Emission test.
3. Cooling system.
4. Fuel system diagnosis.
5. Fuel injector and fuel injector
balance test.
6. EVAP emission canister purge
valve.
7. Crankcase ventilation system.
8. Ignition system.
9. MAP output check.EGR System Check, Exhaust
Diagnosis, Calibration ID/Service
Bulletins
Dieseling, Run-On1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.Ð
Backfire1. OBD system check.
2. Ignition system.
3. Fuel system diagnosis.
4. Fuel injector and fuel injector
balance test.
5. EGR operation, EGR system
check.Exhaust System Diagnosis,
Intake Casting Flash, Ignition
System Check
Misfire1. OBD system check.
2. Ignition system.
3. Fuel system diagnosis.
4. Fuel injector and fuel injector
balance test.Vibrations, Transmission,
Driveshaft and Axle
Catalyst Monitor1. OBD system check.
2. Careful visual/physical inspection.
3. Heated oxygen sensors.Exhaust System
Fuel Trim1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.
4. Heated oxygen sensors, MAF
sensors.Exhaust System Intake Air
System
Evaporative Emissions1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.Ð
Heated Oxygen Sensors1. OBD system check.
2. Careful visual/physical inspection.Exhaust System

6E±545
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Malfunction Indicator Lamp
(MIL)
Removal and Installation Procedure
Refer to Warning light bulb, indicator light valve,
illumination light bulb, A/T indicator light bulb in Meter and
Gauge.
Reduced Power Lamp
The reduced power lamp (RPL) turns on when the ignition
key is moved to the ON position. It should turn off in
approximately 3 seconds or immediately after the engine
starts.
If the RPL turns on during vehicle operation, a vehicle
system failure resulting in reduced engine output is
indicated.
If both the reduced RPL and the check engine light turn
on, a serious problem affecting vehicle performance is
indicated.
Refer to the
OBD system check NO and RPL ªONº steady
in this manual.
Powertrain Control Module
(PCM)
Service Precaution
NOTE: To p r e ve n t p ossible electrostatic discharge
damage to the PCM, do not touch the connector pins or
soldered components on the circuit board.
Electrostatic Discharge (ESD)
Damage
Electronic components used in the control systems are
often designed to carry very low voltage. Electronic
components are susceptible to damage caused by
electrostatic discharge. Less than 100 volts of static
electricity can cause damage to some electronic
components. By comparison, it takes as much as 4,000
volts for a person to even feel the zap of a static
discharge.
There are several ways for a person to become statically
charged. The most common methods of charging are by
friction and by induction. An example of charging by
friction is a person sliding across a car seat.
Charging by induction occurs when a person with well
insulated shoes stands near a highly charged object and
momentarily touches ground. Charges of the same
polarity are drained off leaving the person highly charged
with the opposite polarity. Static charges can cause
damage, therefore, it is important to use care when
handling and testing electronic components.
NOTE: To prevent possible Electrostatic Discharge
damage, follow these guidelines:

Do not touch the control module connector pins or
soldered components on the control module circuit
board.
Do not open the replacement part package until the
part is ready to be installed.

Before removing the part from the package, ground
the package to a known good ground on the vehicle.

If the part has been handled while sliding across the
seat, or while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.
NOTE: To prevent internal PCM damage, the ignition
must be in the ªOFFº position in order to disconnect or
reconnect power to the PCM (for example: battery cable,
PCM pigtail, PCM fuse, jumper cables, etc.).
IMPORTANT:When replacing the production PCM
with a service PCM, it is important to transfer the
broadcast code and production PCM number to the
service PCM label. This will allow positive identification of
PCM parts throughout the service life of the vehicle. Do
not record this information on the metal PCM cover.
IMPORTANT:The ignition should always be in the
ªOFFº position in order to install or remove the PCM
connectors.
Service of the PCM should normally consist of either re-
placement of the PCM or EEPROM programming. If the
diagnostic procedures call for the PCM to be replaced,
the PCM should be checked first to ensure it is the correct
part. If it is, remove the faulty PCM and install the new
service PCM.
The service PCM EEPROM will not be programmed.
DTC P0601 indicates the check sum error.
Removal Procedure
1. Disconnect the negative battery cable.
2. Block the wheels.
3. Remove the two screws from the PCM electrical
connectors.
4. Disconnect the PCM electrical connectors.
060RY00065

6E±547
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
EEPROM
General Description
The Electronically Erasable Programmable Read Only
Memory (EEPROM) is a permanent memory that is
physically soldered within the PCM. The EEPROM
contains program and calibration information that the
PCM needs to control powertrain operation.
EEPROM Programming
1. Set-up ± Ensure that the following conditions have
been met:

The battery is fully charged.

The ignition is ªON.º

The Vehicle Interface Module cable connection at
the DLC is secure.
2. Program the PCM using the latest software matching
the vehicle. Refer to up-to-date Techline equipment
user's instructions.
3. If the PCM fails to program, proceed as follows:

Ensure that all PCM connections are OK.

Check the Techline equipment for the latest
software version.

Attempt to program the PCM. If the PCM still
cannot be programmed properly, replace the PCM.
The replacement PCM must be programmed.
Functional Check
1. Perform the On-Board Diagnostic System Check.
2. Start the engine and run for one minute.
3. Scan for DTCs using the Tech 2.
Throttle Position (TP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the TPS electrical connector.3. Remove the bolts and the TP sensor from the throttle
body.
060RY00159
NOTE: Do not clean the TP sensor by soaking it in
solvent. The sensor will be damaged as a result.
Function Check
Use a Tech 2 to check the TP sensor output voltage at
closed throttle.

The voltage should be TP1 about 0.4V, TP2 about
4.6V and TP3 about 4.6V.

If the reading is abnormal value, check the throttle
shaft to see if it is binding.
Installation Procedure
1. Install the TP sensor on the throttle body with the
bolts.
060RY00159
2. Connect the TP electrical connector.
3. Install the negative battery cable.