2002 ISUZU AXIOM check engine

6E±256
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0300 Engine Misfire Detected
Circuit Description
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ION Sensing
Module. Combustion signals represent the degree of
combustion in each cylinder. Misfire is detected when the
combustion signal is below a predetermined value.
This DTC P0300 will determine if a multiple cylinder
misfire is occurring by monitoring the Combustion
Quality.
Conditions for Setting the DTC

None of the following DTCs occur: TP sensor, MAF
sensor, VSS, ECT sensor.

The engine speed is between 600 and 6250 RPM.

The system voltage is between 11 and 16 volts.

The engine temperature sensor (ECT) indicates an
engine temperature between ±7
C (20
F) and 110
C
(230
F).

Throttle angle is steady and throttle changes 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 disable the TCC operation.

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 trip cycle in which the diagnostic has been
run and the fault condition is no longer present.

A history DTC P0300 will clear after 40 consecutive
warm-up cycles occur without a fault.

DTC P0300 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
The Tech 2 display ªMisfire Cur. #1 through #6º can be
useful to determine whether the misfire is isolated to a
single cylinder.
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.
If the misfire is random, check for the following conditions:

System grounds ± Ensure all connections are clean
and properly tightened.

MAF ± A mass air flow (MAF) sensor output that
causes the PCM to sense a lower than normal air flow
will cause a lean condition.

Air induction system ± Air leaks into the induction
system which bypass the MAF sensor will cause a lean
condition. Check for disconnected or damaged
vacuum hoses, incorrectly installed or faulty PCV
valve, or for vacuum leaks at the throttle body, EGR
valve, and intake manifold mounting surfaces.

Fuel pressure ± Perform a fuel system pressure test.
A faulty fuel pump, plugged filter, or faulty fuel system
pressure regulator will contribute to a lean condition.

Injector(s) ± Perform an injector coil/balance test to
locate faulty injector(s) contributing to a lean or
flooding condition. In addition to the above test, check
the condition of the injector O-rings.

EGR ± Check for a leaking valve, adapter, or feed pipes
which will contribute to a lean condition or excessive
EGR flow.

Fuel quality ± Using fuel with the wrong octane rating
for the vehicle may cause driveability problems.
Although alcohol-enhanced fuels may raise the octane
rating, the fuel's ability to turn into vapor in cold
temperatures deteriorates. This may affect the cold
driveability of the engine. The Reid Vapor Pressure of
the fuel can also create problems in the fuel system,
especially during the spring and fall when changes by
the refineries may not coincide with changes in the
weather.

Vehicle marshalling ± The transportation of new
vehicles from the assembly plant to the dealership can
involve as many as 60 key cycles within 2 to 3 miles of
driving. This type of operation contributes to the fuel
fouling of the spark plugs and will turn on the MIL with
a P0300 Misfire DTC.
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.

6E±257
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0300 ± Engine 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 the Tech 2 Freeze Frame data.
3. Operate the vehicle to duplicate the conditions
present when the DTC was set (as defined by the
Freeze Frame data).
4. Monitor the Tech 2 ªMisfire Cur. #º display for each
cylinder.
Is ªMisfire Cur. #º display increasing for any cylinder
(indicating a misfire currently occurring)?
ÐGo to Step 3
Refer to
Diagnostic
Aids
31. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections.
2. If a problem is found, repair or replace the vacuum
hoses as necessary.
Did your inspection reveal a problem?
ÐVerify repair Go to Step 4
41. Visually and physically inspect the following areas
for vacuum leaks:

The intake manifold

The injector O-rings

The EGR adapter

The EGR feed pipes

ION Sensing Module
2. If a problem is found, repair the vacuum leak as
necessary.
Did your inspection reveal a vacuum leak?
ÐVerify repairGo to Step 5
51. Visually and physically inspect the crankcase
ventilation valve for improper installation or
damaged grommet.
2. If a problem is found, repair as necessary (refer to
Crankcase Ventilation System).
Did your inspection reveal a problem?
ÐVerify repairGo to Step 6
61. Inspect the MAF sensor inlet screen for damage or
for the presence of foreign objects that may partially
block the air flow sample through the MAF sensor.
2. If a problem is found, repair or replace the MAF
sensor as necessary.
Did your inspection of the MAF sensor reveal a
condition requiring repair or replacement?
ÐVerify repairGo to Step 7
71. Remove the EGR valve and visually/physically
inspect the valve to ensure that the pintle is not
sticking partially open. Also, inspect the EGR valve
pintle and seat for carbon deposits or burrs that may
interfere with the pintle closing completely.
2. If a problem is found, clean the EGR valve pintle and
seat or replace the EGR valve as necessary.
Did your inspection reveal a problem?
ÐVerify repairGo to Step 8

6E±258
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0300 ± Engine Misfire Detected

 
StepNo Ye s Value(s) Action
81. Install a spark tester at the spark plug end of the
ignition coil for a cylinder that indicated a misfire.
2. Crank the engine while observing the spark tester.
A crisp, blue spark should be observed.
Is adequate spark present?
ÐGo to Step 14Go to Step 9
91. Remove and visually/physically inspect the ignition
coil(s) associated with the cylinders that were
indicated as misfiring. Ensure that the coil(s) are
free of cracks.
2. If a problem is found, replace the damaged ignition
coil(s) as necessary.
Did any ignition coils require replacement?
ÐVerify repairGo to Step 10
101. Remove the spark plugs from the cylinders that
were indicated as misfiring.
2. Visually inspect the spark plug electrodes.
Does your inspection reveal any spark plugs exhibiting
excessive fouling?
Ð
Go to Engine
Mechanical
Diagnosis
Go to Step 11
111. Visually inspect the spark plug insulators for cracks,
carbon tracking, or other damage.
2. If a problem is found, replace the faulty spark
plug(s) as necessary.
Did your inspection reveal a problem?
ÐVerify repairGo to Step 12
121. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in ªclosed loopº while
monitoring the ªBANK 1 L.T. FUEL TRIMº and
ªBANK 1 S.T. FUEL TRIMº display on the Tech 2.
Do both values decrease below the specified values?ºBANK 1 L.T.
FUEL TRIMº
below +20%;
ªBANK 1 S.T.
FUEL TRIMº
below +50%
Go to Step 13
Replace the
ignition coil of
the affected
cylinder
13Replace the ignition coil control module.
Is the action complete?
ÐVerify repairÐ
141. Visually and physically inspect the PCM injector
grounds, power grounds and sensor grounds to
ensure that they are clean, tight and in their proper
locations.
2. If a problem is found, correct the faulty ground
condition as necessary.
Did your inspection reveal a poor ground?
ÐVerify repair Go to Step 15
151. Perform the ªFuel System Pressure Testº
procedure.
2. If a problem is found, repair as necessary (refer to
Engine Fuel or Fuel Metering System).
Was a fuel system problem found?
ÐVerify repairGo to Step 16
161. Check the fuel for excessive water, alcohol, or other
contaminants (refer to
Diagnosis in Engine Fuel for
procedure).
2. If a problem is found, correct the contaminated fuel
condition as necessary.
Was the fuel contaminated?
ÐVerify repairGo to Step 17

6E±259
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0300 ± Engine Misfire Detected

 
StepNo Ye s Value(s) Action
171. Perform the ªInjector Coil/Balance Testº.
2. If a problem is found, replace faulty injector(s) as
necessary.
Did any of the injectors require replacement?
ÐVerify repairGo to Step 18
181. Check for an engine mechanical problem. Refer to
Engine Mechanical Diagnosis to diagnose the
following conditions:

A faulty or incorrect camshaft

Leaking or sticky valves or rings

Excessive valve deposits

Weak valve springs

Incorrect valve timing

A leaking head gasket

A loose or broken motor mount
2. If a problem is found, repair as necessary.
Was a basic engine mechanical problem found and
repaired?
ÐVerify repairGo to Step 19
191. Check for a transmission TCC problem. Refer to
4L30-E Automatic Transmission Diagnosis.
2. If a problem is found, repair the transmission as
necessary. Refer to
4L30-E Automatic
Transmission Unit Repair
.
Was a transmission problem found and repaired?
ÐVerify repair Go to Step 20
20Replace the MAF sensor.
Is the action complete?
ÐVerify repairÐ

6E±260
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0301 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 P0301 will determine if the No.1 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
±7
C (28
F) and 110
C (230
F).

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 P0301 will clear after 40 consecutive
ignition cycles occur without a fault.

DTC P0301 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 P0301 ± 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. #1º on the Tech 2.
Is ªMisfire Cur. #1º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4Go to Step 3
3Monitor ªMisfire Hist. #1º 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. #1º 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 #1 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

6E±261
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0301 ± Cylinder Misfire Detected

 
StepNo Ye s Value(s) Action
61. Remove and visually/physically inspect the ignition
coil associated with cylinder #1. 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 K
Verify repairGo to Step 12
8Remove the cylinder #1 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

6E±262
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0302 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 P0302 will determine if the No.2 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
±7
C (28
F) and 110
C (230
F).

The throttle angle is steady and throttle change less
than 2% per 125 milliseconds.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

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 P0302 will clear after 40 consecutive
ignition cycles occur without a fault.

DTC P0302 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 P0302 ± 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. #2º on the Tech 2.
Is ªMisfire Cur. #2º increasing (indicating a misfire
currently occurring)?
ÐGo to Step 4Go to Step 3
3Monitor ªMisfire Hist. #2º 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. #2º 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 #2 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

6E±263
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0302 ± Cylinder Misfire Detected

 
StepNo Ye s Value(s) Action
61. Remove and visually/physically inspect the ignition
coil associated with cylinder #2. 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 K
Verify repairGo to Step 12
8Remove the cylinder #2 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 repair Go 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