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
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
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
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
6E±272
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0325
ION Sensing Module/ION Sensing Knock Intensity Circuit Fault
060R200055
Circuit Description
The Power Control Module (PCM) checks the validity of
the signals used in the ION Sensing module at the
following engine operating conditions.
The test is performed to evacuate the Knock Intensity
(KI) signal pulse width if it is within a predetermined
range. If the KI signal pulse width is out of the
predetermined range, the fail counter will be
incremented. If the failure counter exceeds the
calibration, then test is complete and a failure will be
reported. If the sample counter threshold is reached
before the failure threshold, then the test is complete
and a pass will be reported. This test will detect an
open/short in the KI line circuit, ION module faults and
analog input faults in the PCM.
Conditions for setting the DTC
Ignition voltage is between 10volt and 16 volts.
No Crank DTCs set.
No EST DTCs set.
No Misfire DTCs set.
Action Taken When the DTC Sets
The PCM will ON the MIL after second trip with
detected the fault.
The PCM calculates an air flow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.The PCM will store condition 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 P0325 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.
DTC P0325 can be cleared using the Tech2 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.
6E±275
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0336 58X Reference Signal Circuit
060R200066
Circuit Description
The 58X reference signal is produced by the crankshaft
position (CKP) sensor. During one crankshaft revolution,
58 crankshaft pulses will be produced. The powertrain
control module (PCM) uses the 58X reference signal to
calculate engine RPM and crankshaft position. The PCM
constantly monitors the number of pulses on the 58X
reference circuit. If the PCM receives an incorrect
number of pulses on the 58X reference circuit, DTC
P0336 will set.
Conditions for Setting the DTC
Engine is running.
Extra or missing pulse is detected between
consecutive 58X reference pulses.
Above condition is detected in 10 of 100 crankshaft
rotations.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
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 P0336 will clear after 40 consecutive
warm±up cycles have occurred without a fault.
DTC P0336 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
6E±278
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0337 CKP Sensor Circuit Low Frequency
060R200066
Circuit Description
The 58X reference signal is produced by the crankshaft
position (CKP) sensor. During one crankshaft revolution,
58 crankshaft reference pulses will be produced. The
powertrain control module (PCM) uses the 58X reference
signal to calculate engine RPM and crankshaft position.
The PCM constantly monitors the number of pulses on
the 58X reference circuit. If the PCM does not receive
pulses on the 58X reference circuit, DTC P0337 will set.
Conditions for Setting the DTC
Engine cranking.
Crankshaft position (CKP) sensor signal is not present
between two cam pulses.
CKP reference pulse is not detected within 8 CMP
pulses.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
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 P0337 will clear after 40 consecutive
warm-up cycles have occurred without a fault.
DTC P0337 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
6E±281
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0351 Ignition 1 Control Circuit
060R200055
Circuit Description
ION Sensing Module has the function to energize and
de-energize the primary ignition coil in response to
signals from the PCM. The PCM controls ignition timing
and dwell time.
This diagnosis detects open circuit or short-circuiting in
the Ignition Electronic Spark Timing (EST) line by
monitoring EST signals. A failure determination is made
when the signal voltage remains higher or lower than the
threshold for corresponding fault code beyond a
predetermined time period.
When the PCM detects a problem on EST control circuit
1, it will set a DTC P0351.
Conditions for Setting the DTC
The ignition is ªONº.
The engine is running, determined by the 58X
crankshaft position input signal.
The output voltage is not equal to 5 volts when output
is ªONº.The output voltage is not equal to 0 volts when output
is ªOFFº.
Ten test failures occur within 10 samples of continuous
spark events.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
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 P0351 will clear after 40 consecutive
warm-up cycles occur without a fault.
DTC P0351 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.