Page 601 of 5267

P0302-CYLINDER # 2 MISFIRE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
While the engine is idling at operating temperature.
Set Condition:
Misfire detected on this cylinder.
Possible Causes
LOW FUEL
OTHER DTC’S
DAMAGED FUEL LINE
VA LV E T R A I N
OBSTRUCTED FUEL INJECTOR SUPPLY LINE
DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
EXTERNAL DAMAGED FUEL INJECTOR
INTERNAL DAMAGED FUEL INJECTOR
NO COMPRESSION
EXCESSIVE ENGINE LEAK DOWN
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.LOW FUEL
Using the scan tool, verify that the fuel level is above 15%.
Is the fuel level above 15%?
Ye s>>
Go To 2
No>>
Addfuelgotostep2.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.OTHER DTC’S
Read the Freeze frame data.
Is the DTC equal to the freeze frame DTC?
Ye s>>
Go To 3
No>>
Repair any other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 602 of 5267

3.DAMAGED FUEL LINE
Visually inspect the injector supply line for damage.
Do you have any kinked or bent fuel line?
Ye s>>
Repair or replace the damaged fuel line.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
4.VA LV E T R A I N
Visually inspect the valve train and check the valve lash on the suspect cylinder.
Is the valve train functional and the lash within the specifications listed in the service manual?
Ye s>>
Go To 5
No>>
Adjust the lash or fix or repair any damaged component(s).
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.OBSTRUCTED FUEL INJECTOR SUPPLY
Remove the fuel injector supply line for the suspect cylinder.
Inspect both ends of the fuel injector supply line for damage.
Using shop air pressure, blow out the fuel injector supply line to verify that they are not obstructed.
Are the fuel lines free of debris or damage?
Ye s>>
Go To 6
No>>
Replace the damaged or obstructed fuel injector supply line.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
6.DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
Remove the high pressure connector for the suspect cylinder.
Inspect both ends of the high pressure connector for signs of damage.
Using shop air pressure, blow out the high pressure connector to verify that it is not obstructed.
Are the high pressure connectors free of debris or damage?
Ye s>>
Go To 7
No>>
Replace the damaged or obstructed high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.FUEL INJECTOR
Remove the suspect fuel injector.
Is the fuel injector damaged?
Ye s>>
Replace the external damaged fuel injector & high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 8
Page 603 of 5267

8.INTERNAL DAMAGED FUEL INJECTOR
With the scan tool, erase DTCs.
Switch the misfiring injector & high pressure connector with an injector &high pressure connector from a cylinder
that is firing properly.
Operate the vehicle.
Did the misfire DTC follow the suspect injector & high pressure connector?
Ye s>>
Replace the internal damaged fuel injector and high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 9
9.INTERNAL ENGINE DAMAGE
Perform engine compression test
Did the suspect cylinders pass the compression test?
Ye s>>
Go To 10
No>>
Repair the internal damage to the engine.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
10.INTERNAL ENGINE DAMAGE
Perform engine leak down test
Did the suspect cylinders pass the leak down test?
Ye s>>
Te s t C o m p l e t e .
No>>
Repair the internal damage to the engine.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 604 of 5267

P0303-CYLINDER # 3 MISFIRE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
While the engine is idling at operating temperature.
Set Condition:
Misfire detected on this cylinder.
Possible Causes
LOW FUEL
OTHER DTC’S
DAMAGED FUEL LINE
VA LV E T R A I N
OBSTRUCTED FUEL INJECTOR SUPPLY LINE
DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
EXTERNAL DAMAGED FUEL INJECTOR
INTERNAL DAMAGED FUEL INJECTOR
NO COMPRESSION
EXCESSIVE ENGINE LEAK DOWN
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.LOW FUEL
Using the scan tool, verify that the fuel level is above 15%.
Is the fuel level above 15%?
Ye s>>
Go To 2
No>>
Addfuelgotostep2.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.OTHER DTC’S
Read the Freeze frame data.
Is the DTC equal to the freeze frame DTC?
Ye s>>
Go To 3
No>>
Repair any other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 605 of 5267

3.DAMAGED FUEL LINE
Visually inspect the injector supply line for damage.
Do you have any kinked or bent fuel line?
Ye s>>
Repair or replace the damaged fuel line.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
4.VA LV E T R A I N
Visually inspect the valve train and check the valve lash on the suspect cylinder.
Is the valve train functional and the lash within the specifications listed in the service manual?
Ye s>>
Go To 5
No>>
Adjust the lash or fix or repair any damaged component(s).
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.OBSTRUCTED FUEL INJECTOR SUPPLY
Remove the fuel injector supply line for the suspect cylinder.
Inspect both ends of the fuel injector supply lines for damage.
Using shop air pressure, blow out the fuel injector supply lines to verify that they are not obstructed.
Are the fuel lines free of debris or damage?
Ye s>>
Go To 6
No>>
Replace the damaged or obstructed fuel injector supply line.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
6.DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
Remove the high pressure connector for the suspect cylinder.
Inspect both ends of the high pressure connector for signs of damage.
Using shop air pressure, blow out the high pressure connector to verify that it is not obstructed.
Are the high pressure connectors free of debris or damage?
Ye s>>
Go To 7
No>>
Replace the damaged or obstructed high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.FUEL INJECTOR
Remove the suspect fuel injector.
Are the fuel injectors damaged?
Ye s>>
Replace the external damaged fuel injector & high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 8
Page 606 of 5267

8.INTERNAL DAMAGED FUEL INJECTOR
With the scan tool, erase DTCs.
Switch the misfiring injector & high pressure connector with an injector &high pressure connector from a cylinder
that are firing properly.
Operate the vehicle.
Did the misfire DTC follow the suspect injectors & high pressure connectors?
Ye s>>
Replace the internal damaged fuel injector and high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 9
9.INTERNAL ENGINE DAMAGE
Perform engine compression test
Did the suspect cylinders pass the compression test?
Ye s>>
Go To 10
No>>
Repair the internal damage to the engine.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
10.INTERNAL ENGINE DAMAGE
Perform engine leak down test
Did the suspect cylinders pass the leak down test?
Ye s>>
Te s t C o m p l e t e .
No>>
Repair the internal damage to the engine.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 607 of 5267

P0304-CYLINDER # 4 MISFIRE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
While the engine is idling at operating temperature.
Set Condition:
Misfire detected on this cylinder.
Possible Causes
LOW FUEL
OTHER DTC’S
DAMAGED FUEL LINE
VA LV E T R A I N
OBSTRUCTED FUEL INJECTOR SUPPLY LINE
DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
EXTERNAL DAMAGED FUEL INJECTOR
INTERNAL DAMAGED FUEL INJECTOR
NO COMPRESSION
EXCESSIVE ENGINE LEAK DOWN
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.LOW FUEL
Using the scan tool, verify that the fuel level is above 15%.
Is the fuel level above 15%?
Ye s>>
Go To 2
No>>
Addfuelgotostep2.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.OTHER DTC’S
Read the Freeze frame data.
Is the DTC equal to the freeze frame DTC?
Ye s>>
Go To 3
No>>
Repair any other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 608 of 5267

3.DAMAGED FUEL LINE
Visually inspect the injector supply line for damage.
Do you have any kinked or bent fuel line?
Ye s>>
Repair or replace the damaged fuel line.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
4.VA LV E T R A I N
Visually inspect the valve train and check the valve lash on the suspect cylinder.
Is the valve train functional and the lash within the specifications listed in the service manual?
Ye s>>
Go To 5
No>>
Adjust the lash or fix or repair any damaged component(s).
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.OBSTRUCTED FUEL INJECTOR SUPPLY
Remove the fuel injector supply line for the suspect cylinder.
Inspect both ends of the fuel injector supply line for damage.
Using shop air pressure, blow out the fuel injector supply lines to verify that they are not obstructed.
Are the fuel lines free of debris or damage?
Ye s>>
Go To 6
No>>
Replace the damaged or obstructed fuel injector supply line.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
6.DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
Remove the high pressure connector for the suspect cylinder.
Inspect both ends of the high pressure connector for signs of damage.
Using shop air pressure, blow out the high pressure connectors to verify that it is not obstructed.
Are the high pressure connectors free of debris or damage?
Ye s>>
Go To 7
No>>
Replace the damaged or obstructed high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.FUEL INJECTOR
Remove the suspect fuel injector.
Are the fuel injectors damaged?
Ye s>>
Replace the external damaged fuel injector & high pressure connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 8