oil level ISUZU AXIOM 2002 Service Owner's Guide
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Page 1001 of 2100
6E±34
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
dissatisfaction. The following list of non-vehicle faults
does not include every possible fault and may not apply
equally to all product lines.
Fuel Quality
Fuel quality is not a new issue for the automotive industry,
but its potential for turning on the MIL (ªCheck Engineº
lamp) with OBD II systems is new.
Fuel additives such as ªdry gasº and ªoctane enhancersº
may affect the performance of the fuel. If this results in an
incomplete combustion or a partial burn, it will show up as
a Misfire DTC P0300. The Reed Vapor Pressure of the
fuel can also create problems in the fuel system,
especially during the spring and fall months when severe
ambient temperature swings occur. A high Reed Vapor
Pressure could show up as a Fuel Trim DTC due to
excessive canister loading. High vapor pressures
generated in the fuel tank can also affect the Evaporative
Emission diagnostic as well.
Using fuel with the wrong octane rating for the vehicle
may cause driveability problems. Many of the major fuel
companies advertise that using ªpremiumº gasoline will
improve the performance of the vehicle. Most premium
fuels use alcohol to increase the octane rating of the fuel.
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 starting
ability and cold driveability of the engine.
Low fuel levels can lead to fuel starvation, lean engine
operation, and eventually engine misfire.
Non-OEM Parts
All of the OBD II diagnostics have been calibrated to run
with OEM parts. Something as simple as a
high-performance exhaust system that affects exhaust
system back pressure could potentially interfere with the
operation of the EGR valve and thereby turn on the MIL
(ªCheck Engineº lamp). Small leaks in the exhaust
system near the post catalyst oxygen sensor can also
cause the MIL (ªCheck Engineº lamp) to turn on.
Aftermarket electronics, such as transceivers, stereos,
and anti-theft devices, may radiate EMI into the control
system if they are improperly installed. This may cause a
false sensor reading and turn on the MIL (ªCheck Engineº
lamp).
Environment
Temporary environmental conditions, such as localized
flooding, will have an effect on the vehicle ignition system.
If the ignition system is rain-soaked, it can temporarily
cause engine misfire and turn on the MIL (ªCheck Engineº
lamp).
Refueling
A new OBD II diagnostic was introduced in 1996 on some
vehicles. This diagnostic checks the integrity of the entire
evaporative emission system. If the vehicle is restarted
after refueling and the fuel cap is not secured correctly,
the on-board diagnostic system will sense this as a
system fault and turn on the MIL (ªCheck Engineº lamp)
with a DTC P0440.Vehicle Marshaling
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 (ªCheck Engineº lamp) with a P0300
Misfire DTC.
Poor Vehicle Maintenance
The sensitivity of OBD II diagnostics will cause the MIL
(ªCheck Engineº lamp) to turn on if the vehicle is not
maintained properly. Restricted air filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD II. Poor vehicle
maintenance can't be classified as a ªnon-vehicle faultº,
but with the sensitivity of OBD II diagnostics, vehicle
maintenance schedules must be more closely followed.
Related System Faults
Many of the OBD II system diagnostics will not run if the
PCM detects a fault on a related system or component.
One example would be that if the PCM detected a Misfire
fault, the diagnostics on the catalytic converter would be
suspended until Misfire fault was repaired. If the Misfire
fault was severe enough, the catalytic converter could be
damaged due to overheating and would never set a
Catalyst DTC until the Misfire fault was repaired and the
Catalyst diagnostic was allowed to run to completion. If
this happens, the customer may have to make two trips to
the dealership in order to repair the vehicle.
Emissions Control Information Label
The engine compartment ªVehicle Emissions Control
Information Labelº contains important emission
specifications and setting procedures. In the upper left
corner is exhaust emission information. This identifies
the emission standard (Federal, California, or Canada) of
the engine, the displacement of the engine in liters, the
class of the vehicle, and the type of fuel metering system.
There is also an illustrated emission components and
vacuum hose schematic.
This label is located in the engine compartment of every
vehicle. If the label has been removed it should be
replaced. It can be ordered from Isuzu Dealership.
Visual / Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:
Inspect all vacuum hoses for pinches, cuts,
disconnections, and proper routing.
Inspect hoses that are difficult to see behind other
components.
Page 1223 of 2100
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 ±7C (20F) and 110C
(230F).
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.
Page 1227 of 2100
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
±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 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
Page 1229 of 2100
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
±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 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
Page 1231 of 2100
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 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 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 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 1429 of 2100
6E±462
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1311 ION Sensing Module SEC Line 1 Circuit Fault
060R200068
Circuit Description
The Power Control Module (PCM) will compare the
secondary current reading to predetermined maximum
and minimum thresholds.
If the secondary current signal pulse width is out of
the predetermined range, the fail counter will be
incremented. If the failure counter exceeds the
calibration, then the PCM is complete and a failure
will be reported. If the sample counter threshold is
reached before the failure threshold, then the PCM is
complete and pass will be reported.
This PCM will detect an open/short circuit in the
secondary current sense input circuit, misfire on the
entire bank for the secondary current sense input
circuit, coil failure, and same internal Ignition Current
Sense System (ICSS) module faults.
Conditions for setting the DTC
Ignition voltage is between 10volt and 16 volts.
MAP sensor signal is between 26kPa and 100 kPa.
Fuel level is more than 19%.
Engine speed is between 650rpm and 6500rpm.
ION Sensing Module circuit is open or shorted signals
on the SEC 1 line.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM calculates an air flow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.
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 during which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P1311 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.
DTC P1311 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:
Page 1432 of 2100
6E±465
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1312 ION Sensing Module SEC Line 2 Circuit Fault
060R200068
Circuit Description
The Power Control Module (PCM) will compare the
secondary current reading to predetermined maximum
and minimum thresholds.
If the secondary current signal pulse width is out of
the predetermined range, the fail counter will be
incremented. If the fail counter exceeds the
calibration, then the PCM is complete and a failure
will be reported. If the sample counter threshold is
reached before the failure threshold, then the PCM is
complete and pass will be reported.
This PCM will detect an open/short circuit in the
secondary current sense input circuit, misfire on the
entire bank for the secondary current sense input
circuit, coil failure, and same internal Ignition Current
Sense System (ICSS) module faults.
Conditions for setting the DTC
Ignition voltage is between 10volt and 16 volts.
MAP sensor signal is between 26kPa and 100 kPa.
Fuel level is more than 19%.
Engine speed is between 650rpm and 6500rpm.
ION Sensing Module circuit is open or shorted signals
on the SEC 2 line.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM calculates an air flow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.
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 during which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P1312 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.
DTC P1312 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: