check engine ISUZU AXIOM 2002 Service Repair Manual

6E±314
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0420 ± TWC System Low Efficiency Bank 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Are any other DTCs set (such as P0140)?
Ð
Diagnose
other DTC(s)
first
Go to Step 3
31. Visually and physically inspect the three-way
catalytic converter for damage. Check for the
following:

dents

severe discoloration caused by excessive
temperatures

holes

internal rattle caused by damaged catalyst
2. Also, ensure that the three-way catalytic converter
is a proper original equipment manufacturer part.
Did your inspection reveal a problem?
ÐGo to Step 6Go to Step 4
41. Visually and physically inspect the exhaust system
between the three-way catalytic converter and the
rear converter flange for leaks, damage, and loose
or missing hardware.
2. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 5
51. Visually and physically inspect the Bank 1 HO2S 2.
2. Ensure that the Bank 1 HO2S 2 is secure and that
the pigtail and wiring harness is not contacting the
exhaust pipe or is not otherwise damaged.
3. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 6
6Replace the three-way catalytic converter.
NOTE: Check for conditions which may cause catalyst
damage (refer to
Diagnostic Aids).
Is the action complete?
Ð
Go to Step 7
to verify
repair
Ð
71. Review and record the Tech 2 Failure Records data.
2. Clear DTC P0420.
3. Start the engine and allow it to warm up until the
engine coolant temperature monitored on the Tech
2 is above the specified value.
4. Run the engine to maintain the specified mass air
flow range for at least 2 minutes.
5. Operate the vehicle to maintain DTC P0420 test
conditions (refer to
DTC Test Description in
Diagnostic Support for detailed instructions).
6. Using a Tech 2, monitor ªDTCº info for DTC P0420
until the DTC P0420 test runs.
7. Note the test result.
Does the Tech 2 indicate DTC P0420 passed this
ignition?
Engine
coolant temp:
greater than
60
C
(140
F).
Mass air flow:
between 8
g/second and
50 g/second
Complete
repair. If a
driveability
symptom still
exists, refer
to
Symptoms.
Go to the
Diagnostic
Aids

6E±316
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:

Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.

Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
display on the Tech 2 while moving connectors and
wiring harnesses related to the sensor. A change in the
display will indicate the location of the fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
7. Difficulty completing the DTC P0430 ªStatus This
Ignº, test may be encountered in areas where test
conditions cannot be maintained easily, especially in
urban areas. To minimize the amount of driving
required to complete the DTC P0430 ªStatus This
Ignº, test, use the following procedure:

Allow the engine to warm up completely.

With the vehicle in ªParkº, monitor mass air flow on
the Tech 2 and hold part throttle to maintain a
reading of over 12 g/second for at least 2 minutes.
This will achieve the ªwarm catalystº required for
running the test.

Operate the vehicle in second or third gear to remain
in the DTC P0430 test conditions described in
ªConditions for Setting the DTCº as much as
possible. If you must stop the vehicle, maintain the
ªwarm catalystº criteria as follows:
± Place the vehicle in ªParkº or ªNeutralº,
± Hold part throttle to maintain a mass air flow
reading of over 15 g/second for the duration of the
stop.
The ªTWC Monitor Test Counterº displayed on the Tech 2
may be used to monitor the progress of the TWC
diagnostic. To complete the TWC diagnostic with a good
catalyst, the counter must be allowed to increment to 49
samples and roll over to 0 at least twice.

6E±317
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0430 ± TWC System Low Efficiency Bank 2

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Are any other DTCs set (such as P0160)?
Ð
Diagnose
other DTC(s)
first
Go to Step 3
31. Visually and physically inspect the three-way
catalytic converter for damage. Check for the
following:

dents

severe discoloration caused by excessive
temperatures

holes

internal rattle caused by damaged catalyst
2. Also, ensure that the three-way catalytic converter
is a proper original equipment manufacturer part.
Did your inspection reveal a problem?
ÐGo to Step 6Go to Step 4
41. Visually and physically inspect the exhaust system
between the three-way catalytic converter and the
rear converter flange for leaks, damage, and loose
or missing hardware.
2. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 5
51. Visually and physically inspect the Bank 2 HO2S 2.
2. Ensure that the Bank 2 HO2S 2 is secure and that
the pigtail and wiring harness is not contacting the
exhaust pipe or is not otherwise damaged.
3. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 6
6Replace the three-way catalytic converter.
NOTE: Check for conditions which may cause catalyst
damage (refer to
Diagnostic Aids).
Is the action complete?
Ð
Go to Step 7
to verify
repair
Ð
71. Review and record the Tech 2 Failure Records data.
2. Clear DTC P0430.
3. Start the engine and allow it to warm up until the
engine coolant temperature monitored on the Tech
2 is above the specified value.
4. Run the engine to maintain the specified mass air
flow range for at least 6 minutes.
5. Operate the vehicle to maintain DTC P0430 test
conditions (refer to
DTC Test Description in
Diagnostic Support for detailed instructions).
6. Using a Tech 2, monitor ªDTCº info for DTC P0430
until the DTC P0430 test runs.
7. Note the test result.
Does the Tech 2 indicate DTC P0430 passed this
ignition?
Engine
coolant temp:
greater than
70
C
(158
F).
Mass air flow:
between 2.5
g/second and
10 g/second
Complete
repair. If a
driveability
symptom still
exists, refer
to
Symptoms.
Go to the
Diagnostic
Aids

6E±319
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Engine speed is less than 1200 RPM.

Above conditions are present for 60 to 180 seconds.
Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

The PCM will store conditions which were present
when the DTC set as Freeze Frame and in the Failure
Records data.
Conditions for Clearing the MIL/DTC

The PCM will turn the MIL ªOFFº when the diagnostic
has been run and the fault condition is no longer
present.

A history DTC P0440 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0440 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Cracked or punctured EVAP canister.

Damaged or disconnected source vacuum line, EVAP
purge line, vent hose or fuel tank vapor line.

Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness±Inspect the wiring harness to the
EVAP canister vent solenoid, EVAP canister purge
solenoid and the fuel tank pressure sensor for an
intermittent open or short circuit.

Kinked, pinched, or plugged vacuum source, EVAP
purge, or fuel tank vapor line±Verify that the lines are
not restricted.Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If an EVAP canister vent solenoid or an EVAP
canister purge solenoid electrical fault is present,
the purge system will not operate correctly.
Repairing the electrical fault will very likely correct
the condition that set DTC P0440.
3. Checks the fuel tank pressure sensor at ambient
pressure.
4. Determines whether or not the EVAP system can be
sealed sufficiently to be pressurized. If not, the
large leak must be located and corrected before
continuing with diagnosis.
5. Verifies that the fuel tank pressure sensor accurately
reacts to EVAP system pressure changes.
8. Checks for a blocked EVAP canister purge solenoid.
The PCM commands the EVAP canister purge
solenoid ªOFFº (open) and the vent solenoid ªONº
(closed) with the Tech 2 ªSystem Perfº, EVAP
output control function activated. Any pressure in
the system should be released through the EVAP
canister purge solenoid within a few seconds when
ªSystem Perfº, is activated.
9. Ensures that sufficient source vacuum is present at
the EVAP canister purge solenoid.
DTC P0440 ± EVAP System

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Is DTC P0452 or P0453 also set?
Ð
Go to other
DTC first
Go to Step 3
31. Ignition ªOFFº.
2. Remove the fuel cap.
3. Ignition ªONº.
4. Observe ªFuel Tank Pressureº on the Tech 2.
Does the Tech 2 indicate ªFuel Tank Pressureº at the
specified value?
1.51 VGo to Step 4
Go to DTC
P0452
or
DTC P0453
41. Replace the fuel cap.
2. Engine is running.
3. Observe ªFuel Tank Vacuumº on the Tech 2.
Does Tech 2 indicate ªFuel Tank Vacuumº at the
specified value?
1.47±1.51 VGo to Step 7Go to Step 6

6E±320
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0440 ± EVAP System

 
StepNo Ye s Value(s) Action
5Ignition ªOFFº.
1. Disconnect the fuel tank vapor line and the EVAP
purge line from the EVAP canister.
2. Block the canister fitting for the fuel tank vapor line.
3. Connect a hand vacuum pump to the canister fitting
for the EVAP purge line.
4. Ensure that the EVAP canister vent solenoid is still
commanded ªONº (closed).
5. Attempt to apply vacuum to the EVAP canister.
Observe ªFuel tank pressureº on the Tech 2.
Does the Tech 2 indicate ªFuel tank pressureº at the
specified value?
1.47±1.51 VGo to Step 8Go to Step 7
61. Visually/physically check for the following
conditions:

Restricted fuel tank vapor line.

Restricted EVAP purge line.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Go to DTC
P0452
or
DTC P0453
71. Visually/physically check for the following
conditions:

Vent hose disconnected or the damaged.

EVAP canister damaged.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
81. Visually/physically check for the following
conditions:

Missing or faulty fuel cap.

Disconnected or leaking fuel tank vapor line.

Disconnected or damaged EVAP purge line.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 9
9Replace the EVAP canister purge solenoid.
Is the action complete?
ÐVerify repairÐ
10Locate and repair cause of no source vacuum to the
EVAP canister purge solenoid.
Is the action complete?
ÐVerify repairÐ
11Replace the EVAP canister vent solenoid.
Is the action complete?
ÐVerify repairÐ

6E±322
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:

Cracked or punctured EVAP canister.

Damaged source vacuum line, EVAP purge line, EVAP
vent hose or fuel tank vapor line.

Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness±Inspect the wiring harness to the
EVAP canister vent solenoid, EVAP canister purge
solenoid and the fuel tank pressure sensor for an
intermittent open or short circuit.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how oftenthe condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If an EVAP canister vent solenoid or an EVAP
canister purge solenoid electrical fault is present,
the purge system will not operate correctly.
Repairing the electrical fault will very likely correct
the condition that set DTC P0442.
3. Checks the fuel tank pressure sensor at ambient
pressure.
4. Verifies that the fuel tank pressure sensor accurately
reacts to EVAP system pressure changes.
DTC P0442 ± EVAP System Leak Detected

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªOFFº.
2. Remove the fuel cap.
3. Ignition ªONº.
4. Observe ªFuel Tank Pressureº on the Tech 2.
Does the Tech 2 indicate ªFuel Tank Pressureº at the
specified value?
1.51VGo to Step 3
Go to Fuel
Tank
Pressure
System
3IMPORTANT:Before continuing with diagnosis, zero
the EVAP pressure and vacuum gauges on EVAP
pressure/purge cart J 41413 (refer to tool operating
instructions).
1. Replace the fuel cap.
2. Capture Failure Records data for DTC P0442 and
clear DTCs.
3. Connect the EVAP pressure/purge cart J 41413 to
the EVAP service port.
4. Using the Tech 2, command the EVAP canister vent
solenoid ªONº (closed).
5. Using the EVAP pressure/purge cart J 41413,
pressurize the EVAP system to the specified value.
6. Observe ªFuel Tank Pressureº on the Tech 2.
Does the Tech 2 indicate ªFuel Tank Pressureº at the
specified value?
1.47VGo to Step 4
Go to Fuel
Tank
Pressure
System
41. Ignition ªONº, engine idling.
2. Using the Tech 2, command the EVAP canister vent
solenoid ªONº (closed).
3. Using the EVAP pressure/purge cart J 41413,
pressurize the EVAP system to 15 in. H
2O.
4. Switch the rotary switch on the cart to ªHOLDº and
observe the EVAP pressure gauge.
Does the pressure decrease to less than the specified
value within 2 minutes?
1.47 ± 1.51VGo to Step 5
Refer to
Diagnostic
Aids

6E±323
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0442 ± EVAP System Leak Detected

 
StepNo Ye s Value(s) Action
51. Disconnect the fuel tank vapor line and the EVAP
purge line from the EVAP canister.
2. Block the canister fitting for the fuel tank vapor line.
3. Connect a hand vacuum pump to the canister fitting
for the EVAP purge line.
4. Ensure that the EVAP canister vent solenoid is still
commanded ªONº (closed).
5. Attempt to apply vacuum to the EVAP canister.
Can the vacuum be maintained at the specific value?
1.46VGo to Step 8Go to Step 6
61. Visually/physically check for the following
conditions:

Vent hose disconnected or damaged.

EVAP canister damaged.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐGo to Step 10Go to Step 7
7Replace the EVAP canister vent solenoid.
Is the action complete?
ÐGo to Step 10Ð
81. Visually/physically check for the following
conditions:

Missing or faulty fuel cap.

Disconnected or leaking fuel tank vapor line.

Disconnected or damaged EVAP purge line.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐGo to Step 10Go to Step 9
91. Using Tech 2, command the EVAP canister vent
solenoid ªONº (closed).
2. With the cart connected to the EVAP service port,
continuously attempt to pressurize the EVAP
system by leaving the cart control knob in the
pressurize position.
3. Using ultrasonic leak detector J 41416, locate and
repair leak in EVAP system. (It may be necessary to
partially lower the fuel tank to examine the
connections on top of the tank.)
Is the action complete?
ÐGo to Step 10Ð
101. Ignition ªONº, engine not running.
2. Using the Tech 2, command the EVAP canister vent
solenoid ªONº (closed).
3. Using the EVAP pressure/purge cart J 41413,
pressurize and monitor the EVAP system to 15 in.
H
2O.
4. Switch the rotary switch on the cart to ªHOLDº and
observe the EVAP pressure gauge.
Does the pressure decrease to less than the specified
value within 2 minutes?
2.14VGo to Step 2Verify repair

6E±324
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0444 EVAP Purge Control Circuit Open
060RY00398
Circuit Description
The canister purge solenoid valve is controlled by the
Power Train Control Module (PCM).The PCM monitors
vacuum level via the fuel tank pressure sensor input.
At an appropriate time, the EVAP canister purge solenoid
is ªON,º allowing engine vacuum to draw a small vacuum
on the entire evaporative emissions system.
Conditions for setting the DTC

The Ignition is ªONº.

Engine is running.

System voltage is between 11.5 volts and 16 volts.
Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).

The PCM will store conditions which were present
when the DTC was set in the Failure Records data only.
Conditions for Clearing the MIL/DTC

The PCM will turn the MIL ªOFFº on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0444 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.
DTC P0444 can be cleared using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
An intermittent may be caused by the following:

Poor connections.

Mis routed harness.

Rubbed through wire insulation.

Broken wire inside the insulation.
Check for the following conditions:

Poor connection at PCM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
EVAP purge solenoid display on the Tech 2 while
moving connectors and wiring harnesses related to the
sensor.
A change in the display will indicate the location of
the fault. If DTC P0444 cannot be duplicated, the
information included in the Failure Records data can
be useful in determined vehicle mileage since the
DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0444 Diagnostic Chart may
isolate the cause of the fault.

6E±325
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0444 EVAP Purge Control Circuit Open

StepActionValue(s)Ye sNo
1Was the ªOn-Board (OBD) System Checkº performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Install the Tech 2.
2. Ignition is ªONº,
3. Engine is ªONº and operate the accelerator pedal
for 3 or 4 times.
4. Observe the EVAP purge solenoid reading on the
Tech 2.
Is the EVAP purge solenoid reading near the specified
value?
More than 1%
Refer to
Diagnostic
Aids
Go to Step 3
3Check the power supply circuit.
1. Ignition is ªOFFº.
2. Disconnect the canister purge solenoid valve.
3. Ignition is ªONº.
4. Using a DVM, measure at the EVAP purge solenoid
connector between ground and voltage supply.
Was the measurement near the specified value?
Battery
voltage
Go to Step 4Go to Step 5
4Check the signal circuit for the EVAP purge solenoid.
1. Ignition is ªOFFº.
2. Disconnect the canister purge solenoid valve.
3. Disconnect the PCM.
4. Check the circuit between EVAP purge solenoid
connector and PCM connector.
Is the problem found?
ÐGo to Step 5Go to Step 6
5Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
6Check the canister purge solenoid valve. Using a DVM,
measure resistance for purge solenoid valve connector
terminal.
Is the purge solenoid valve resistance within the
specified values?
25±30
(at
68
F{20
C})
Go to Step 8Go to Step 7
7Replace the canister purge solenoid valve.
Is the action complete?
ÐVerify repairÐ
8Replace the
IMPORTANT:The replacement PCM must be
programmed.
Refer to
ON-Vehicle Service in Power Control Module
and Sensors for procedures
.
And also refer to latest Service Bulletin. Check to see
if the latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±326
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0445 EVAP Purge Control Circuit Short
060RY00398
Circuit Description
The canister purge solenoid valve is controlled by the
Power Train Control Module (PCM). The PCM monitors
vacuum level via the fuel tank pressure sensor input.
At an appropriate time, the EVAP canister purge solenoid
is ªON,º allowing engine vacuum to draw a small vacuum
on the entire evaporative emissions system.
Conditions for setting the DTC

The Ignition is ªONº.

Engine is running.

System voltage is between 11.5 volts and 16 volts.
Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).

The PCM will store conditions which were present
when the DTC was set in the Failure Records data only.
Conditions for Clearing the MIL/DTC

The PCM will turn the MIL ªOFFº on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0445 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.
DTC P0445 can be cleared using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
An intermittent may be caused by the following:

Poor connections.

Misrouted harness.

Rubbed through wire insulation.

Broken wire inside the insulation.
Check for the following conditions:

Poor connection at PCM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
EVAP purge solenoid display on the Tech 2 while
moving connectors and wiring harnesses related to the
sensor.
A change in the display will indicate the location of
the fault. If DTC P0445 cannot be duplicated, the
information included in the Failure Records data can
be useful in determined vehicle mileage since the
DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0445 Diagnostic Chart may
isolate the cause of the fault.