2002 ISUZU AXIOM check engine
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6E±264
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0303 Cylinder Misfire Detected
Circuit Description
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ignition current
sense system. Combustion signals represent the degree
of combustion in each cylinder. Misfire is detected when
the combustion signal is below a predetermined value.
This DTC P0303 will determine if the No.3 cylinder misfire
is occurring by monitoring the Combustion Quality.
Conditions for Setting the DTC
None of the following DTCs occur: TP sensor, MAF
sensor, vehicle speed sensor, ECT sensor.
The engine speed is between 600 and 6250 RPM.
The system voltage is between 11 and 16 volts.
The ECT indicates an engine temperature between
±7C (28F) and 110C (230F).
The throttle angle is steady and throttle change less
than 2% per 125 milliseconds.
Action Taken When the DTC Sets
The PCM will ON the MIL after second trip with
detected the fault.
If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº on the third
consecutive ignition cycle in which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P0303 will clear after 40 consecutive
ignition cycles occur without a fault.
DTC P0303 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:
System grounds ± Ensure all connections are clean
and properly tightened.
Injector Ð Perform the injector coil/balance test to
locate a faulty injector that contributes to a lean
condition on the affected cylinder. In addition to the
above test, check the condition of the injector O-ring.
Faulty spark plug ± Check for a cracked insulator,
carbon tracking, incorrect gap, and worn electrodes.
Damaged or faulty ignition coil ± Check for cracks,
carbon tracking or other damage.
Substitute a known good coil ± Swap the ignition coils
and retest. If the misfire follows the coil, replace the
ignition coil.
DTC P0303 ± Cylinder Misfire Detected
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Start the engine. Run the engine at idle.
2. Review and record Tech 2 Freeze Frame data.
3. Monitor ªMisfire Cur. #3º on the Tech 2.
Is ªMisfire Cur. #3º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4Go to Step 3
3Monitor ªMisfire Hist. #3º while operating the vehicle to
duplicate the conditions present when the DTC was set
(as defined by the Freeze Frame data recorded in Step
2).
Is ªMisfire Hist. #3º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections. Also,
inspect the intake manifold for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 5
51. Install a spark tester at the spark plug end of the
cylinder #3 ignition coil.
2. Crank the engine while observing the spark tester.
A crisp, blue spark should be observed.
Is adequate spark present?
ÐGo to Step 8Go to Step 6
Page 1232 of 2100
6E±265
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0303 ± Cylinder Misfire Detected
StepNo Ye s Value(s) Action
61. Remove and visually/physically inspect the ignition
coil associated with cylinder #3. Ensure that the coil
is free of cracks and carbon tracking.
2. If a problem is found, replace the damaged ignition
coil as necessary.
Did the visual inspection reveal a problem?
ÐVerify repairGo to Step 7
71. Measure the ignition coil primary resistance.
2. If resistance is not within the specified value,
replace the faulty ignition coil.
Did the ignition coil require replacement?
2.6-2.7 KVerify repairGo to Step 12
8Remove the cylinder #3 spark plug and visually inspect
the spark plug electrode.
Does the inspection reveal excessive fouling?
Ð
Go to
Contaminatio
n Diagnosis
chart in
Engine
Mechanical
Diagnosis
Go to Step 9
91. Visually inspect the spark plug insulator for cracks,
carbon tracking, or other damage.
2. If the spark plug is damaged, replace the spark plug.
Did the inspection reveal a problem?
ÐVerify repair Go to Step 10
101. Perform the ªInjector Coil/Balance Testº.
2. If any faulty injectors are found, replace them as
necessary.
Did any of the injectors require replacement?
ÐVerify repairGo to Step 11
111. Inspect the injector O-rings for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 12
12Check for an engine mechanical problem. Refer to
Engine Mechanical Diagnosis to diagnose and repair
the following conditions:
A faulty or incorrect camshaft
Leaking or sticky valves or rings
Excessive valve deposits
Weak valve springs
A leaking head gasket
Was a basic engine mechanical problem found?
ÐVerify repair
Refer to
Diagnostic
Aids
Page 1233 of 2100
6E±266
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0304 Cylinder Misfire Detected
Circuit Description
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ignition current
sense system. Combustion signals represent the degree
of combustion in each cylinder. Misfire is detected when
the combustion signal is below a predetermined value.
This DTC P0304 will determine if the No.4 cylinder misfire
is occurring by monitoring the Combustion Quality.
Conditions for Setting the DTC
None of the following DTCs occur: TP sensor, MAF
sensor, vehicle speed sensor, ECT sensor.
The engine speed is between 600 and 6250 RPM.
The system voltage is between 11 and 16 volts.
The ECT indicates an engine temperature between
±7C (28F) and 110C (230F).
The throttle angle is steady and throttle change less
than 2% per 125 milliseconds.
Action Taken When the DTC Sets
The PCM will ON the MIL after second trip with
detected the fault.
If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº on the third
consecutive ignition cycle in which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P0304 will clear after 40 consecutive
ignition cycles occur without a fault.
DTC P0304 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:
System grounds ± Ensure all connections are clean
and properly tightened.
Injector ± Perform the injector coil/balance test to
locate a faulty injector that contributes to a lean
condition on the affected cylinder. In addition to the
above test, check the condition of the injector O-ring.
Faulty spark plug ± Check for a cracked insulator,
carbon tracking, incorrect gap, and worn electrodes.
Damaged or faulty ignition coil ± Check for cracks,
carbon tracking or other damage.
Substitute a known good coil ± Swap the ignition coils
and retest. If the misfire follows the coil, replace the
ignition coil.
DTC P0304 ± Cylinder Misfire Detected
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Start the engine. Run the engine at idle.
2. Review and record Tech 2 Freeze Frame data.
3. Monitor ªMisfire Cur. #4º on the Tech 2.
Is ªMisfire Cur. #4º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4Go to Step 3
3Monitor ªMisfire Hist. #4º while operating the vehicle to
duplicate the conditions present when the DTC was set
(as defined by the Freeze Frame data recorded in Step
2).
Is ªMisfire Hist. #4º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections. Also,
inspect the intake manifold for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 5
51. Install a spark tester at the spark plug end of the
cylinder #4 ignition wire.
2. Crank the engine while observing the spark tester.
A crisp, blue spark should be observed.
Is adequate spark present?
ÐGo to Step 8Go to Step 6
Page 1234 of 2100
6E±267
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0304 ± Cylinder Misfire Detected
StepNo Ye s Value(s) Action
61. Remove and visually/physically inspect the ignition
coil associated with cylinder #4. Ensure that the coil
is free of cracks and carbon tracking.
2. If a problem is found, replace the damaged ignition
coil as necessary.
Did the visual inspection reveal a problem?
ÐVerify repair Go to Step 7
71. Measure the ignition coil primary resistance.
2. If resistance is not within the specified value,
replace the faulty ignition coil.
Did the ignition coil require replacement?
2.6-2.7 KVerify repairGo to Step 12
8Remove the cylinder #4 spark plug and visually inspect
the spark plug electrode.
Does the inspection reveal excessive fouling?
Ð
Go to
Contaminatio
n Diagnosis
chart in
Engine
Mechanical
Diagnosis
Go to Step 9
91. Visually inspect the spark plug insulator for cracks,
carbon tracking, or other damage.
2. If the spark plug is damaged, replace the spark plug.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 10
101. Perform the ªInjector Coil/Balance Testº.
2. If any faulty injectors are found, replace them as
necessary.
Did any of the injectors require replacement?
ÐVerify repairGo to Step 11
111. Inspect the injector O-rings for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 12
12Check for an engine mechanical problem. Refer to
Engine Mechanical Diagnosis to diagnose and repair
the following conditions:
A faulty or incorrect camshaft
Leaking or sticky valves or rings
Excessive valve deposits
Weak valve springs
A leaking head gasket
Was a basic engine mechanical problem found?
ÐVerify repair
Refer to
Diagnostic
Aids
Page 1235 of 2100
6E±268
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0305 Cylinder Misfire Detected
Circuit Description
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ignition current
sense system. Combustion signals represent the degree
of combustion in each cylinder. Misfire is detected when
the combustion signal is below a predetermined value.
This DTC P0305 will determine if the No.5 cylinder misfire
is occurring by monitoring the Combustion Quality.
Conditions for Setting the DTC
None of the following DTCs occur: TP sensor, MAF
sensor,vehicle speed sensor, ECT sensor.
The engine speed is between 600 and 6250 RPM.
The system voltage is between 11 and 16 volts.
The ECT indicates an engine temperature between
±7C (28F) and 110C (230F).
The throttle angle is steady and throttle change less
than 2% per 125 milliseconds.
Action Taken When the DTC Sets
The PCM will ON the MIL after second trip with
detected the fault.
If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº on the third
consecutive ignition cycle in which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P0305 will clear after 40 consecutive
ignition cycles occur without a fault.
DTC P0305 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:
System grounds ± Ensure all connections are clean
and properly tightened.
Injector ± Perform the injector coil/balance test to
locate a faulty injector that contributes to a lean
condition on the affected cylinder. In addition to the
above test, check the condition of the injector O-ring.
Faulty spark plug ± Check for a cracked insulator,
carbon tracking, incorrect gap, and worn electrodes.
Damaged or faulty ignition coil ± Check for cracks,
carbon tracking or other damage.
Substitute a known good coil ± Swap the ignition coils
and retest. If the misfire follows the coil, replace the
ignition coil.
DTC P0305 ± Cylinder Misfire Detected
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Start the engine. Run the engine at idle.
2. Review and record Tech 2 Freeze Frame data.
3. Monitor ªMisfire Cur. #5º on the Tech 2.
Is ªMisfire Cur. #5º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4Go to Step 3
3Monitor ªMisfire Hist. #5º while operating the vehicle to
duplicate the conditions present when the DTC was set
(as defined by the Freeze Frame data recorded in Step
2).
Is ªMisfire Hist. #5º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections. Also,
inspect the intake manifold for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repair Go to Step 5
51. Install a spark tester at the spark plug end of the
cylinder #5 ignition wire.
2. Crank the engine while observing the spark tester.
A crisp, blue spark should be observed.
Is adequate spark present?
ÐGo to Step 8Go to Step 6
Page 1236 of 2100
6E±269
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0305 ± Cylinder Misfire Detected
StepNo Ye s Value(s) Action
61. Remove and visually/physically inspect the ignition
coil associated with cylinder #5. Ensure that the coil
is free of cracks and carbon tracking.
2. If a problem is found, replace the damaged ignition
coil as necessary.
Did the visual inspection reveal a problem?
ÐVerify repairGo to Step 7
71. Measure the ignition coil primary resistance.
2. If resistance is not within the specified value,
replace the faulty ignition coil.
Did the ignition coil require replacement?
2.6-2.7 KVerify repairGo to Step 12
8Remove the cylinder #5 spark plug and visually inspect
the spark plug electrode.
Does the inspection reveal excessive fouling?
Ð
Go to
Contaminatio
n Diagnosis
chart in
Engine
Mechanical
Diagnosis
Go to Step 9
91. Visually inspect the spark plug insulator for cracks,
carbon tracking, or other damage.
2. If the spark plug is damaged, replace the spark plug.
Did the inspection reveal a problem?
ÐVerify repair Go to Step 10
101. Perform the ªInjector Coil/Balance Testº.
2. If any faulty injectors are found, replace them as
necessary.
Did any of the injectors require replacement?
ÐVerify repairGo to Step 11
111. Inspect the injector O-rings for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 12
12Check for an engine mechanical problem. Refer to
Engine Mechanical Diagnosis to diagnose and repair
the following conditions:
A faulty or incorrect camshaft
Leaking or sticky valves or rings
Excessive valve deposits
Weak valve springs
A leaking head gasket
Was a basic engine mechanical problem found?
ÐVerify repair
Refer to
Diagnostic
Aids
Page 1237 of 2100
6E±270
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0306 Cylinder Misfire Detected
Circuit Description
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ignition current
sense system. Combustion signals represent the degree
of combustion in each cylinder. Misfire is detected when
the combustion signal is below a predetermined value.
This DTC P0306 will determine if the No.6 cylinder misfire
is occurring by monitoring the Combustion Quality.
Conditions for Setting the DTC
None of the following occur: TP sensor, MAF sensor,
vehicle speed sensor, ECT sensor.
The engine speed is between 600 and 6250 RPM.
The system voltage is between 11 and 16 volts.
The ECT indicates an engine temperature between
±7C (28F) and 110C (230F).
The throttle angle is steady and throttle change less
than 2% per 125 milliseconds.
Action Taken When the DTC Sets
The PCM will ON the MIL after second trip with
detected the fault.
If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº on the third
consecutive ignition cycle in which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P0306 will clear after 40 consecutive
ignition cycles occur without a fault.
DTC P0306 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:
System grounds ± Ensure all connections are clean
and properly tightened.
Injector ± Perform the injector coil/balance test to
locate a faulty injector that contributes to a lean
condition on the affected cylinder. In addition to the
above test, check the condition of the injector O-ring.
Faulty spark plug ± Check for a cracked insulator,
carbon tracking, incorrect gap, and worn electrodes.
Damaged or faulty ignition coil ± Check for cracks or
other damage.
Substitute a known good coil ± Swap the ignition coils
and retest. If the misfire follows the coil, replace the
ignition coil.
DTC P0306 ± Cylinder Misfire Detected
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Start the engine. Run the engine at idle.
2. Review and record Tech 2 Freeze Frame data.
3. Monitor ªMisfire Cur. #6º on the Tech 2.
Is ªMisfire Cur. #6º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4Go to Step 3
3Monitor ªMisfire Hist. #6º while operating the vehicle to
duplicate the conditions present when the DTC was set
(as defined by the Freeze Frame data recorded in Step
2).
Is ªMisfire Hist. #6º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections. Also,
inspect the intake manifold for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 5
51. Install a spark tester at the spark plug end of the
cylinder #6 ignition wire.
2. Crank the engine while observing the spark tester.
A crisp, blue spark should be observed.
Is adequate spark present?
ÐGo to Step 8Go to Step 6
Page 1238 of 2100
6E±271
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0306 ± Cylinder Misfire Detected
StepNo Ye s Value(s) Action
61. Remove and visually/physically inspect the ignition
coil associated with cylinder #6. Ensure that the coil
is free of cracks and carbon tracking.
2. If a problem is found, replace the damaged ignition
coil as necessary.
Did the visual inspection reveal a problem?
ÐVerify repairGo to Step 7
71. Measure the ignition coil primary resistance.
2. If resistance is not within the specified value,
replace the faulty ignition coil.
Did the ignition coil require replacement?
2.6-2.7 KVerify repair Go to Step 12
8Remove the cylinder #6 spark plug and visually inspect
the spark plug electrode.
Does the inspection reveal excessive fouling?
Ð
Go to
Contaminatio
n Diagnosis
chart in
Engine
Mechanical
Diagnosis
Go to Step 9
91. Visually inspect the spark plug insulator for cracks,
carbon tracking, or other damage.
2. If the spark plug is damaged, replace the spark plug.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 10
101. Perform the ªInjector Coil/Balance Testº.
2. If any faulty injectors are found, replace them as
necessary.
Did any of the injectors require replacement?
ÐVerify repairGo to Step 11
111. Inspect the intake manifold and the injector O-rings
for a vacuum leak.
2. If a problem is found, repair it as necessary.
Did the inspection reveal a problem?
ÐVerify repairGo to Step 12
12Check for an engine mechanical problem. Refer to
Engine Mechanical Diagnosis to diagnose and repair
the following conditions:
A faulty or incorrect camshaft
Leaking or sticky valves or rings
Excessive valve deposits
Weak valve springs
A leaking head gasket
Was a basic engine mechanical problem found?
ÐVerify repair
Refer to
Diagnostic
Aids