P0306

P0306-CYLINDER 6 MISFIRE

For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The crankshaft position and camshaft position sensors are hall effect type sensors. The ECM provides a 5-volt supply to the position sensor and a return circuit. As the teeth on the crankshaft speed ring or the lobes on the camshaft gear passes past the position sensor, a signal is generated on the position sensor signal circuit. The ECM interprets this signal and coverts it to an engine speed. A missing tooth on the crankshaft gear is used to determine the position of the engine by the ECM.

- When Monitored:
While the engine is idling at operating temperature.

- Set Condition:
Misfire detected on this cylinder.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. LOW FUEL
Using the scan tool, verify that the fuel level is above 15%.
Is the fuel level above 15%?

Yes


- Go To 2


No


- Add fuel go to step 2.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



2. OTHER DTC'S
Read the Freeze frame data.
Is the DTC equal to the freeze frame DTC?

Yes


- Go To 3


No


- Repair any other DTC's first.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



3. DAMAGED FUEL LINE
Visually inspect the injector supply line for damage.
Do you have any kinked or bent fuel line?

Yes


- Repair or replace the damaged fuel line.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 4



4. VALVE TRAIN
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?

Yes


- Go To 5


No


- Adjust the lash or fix or repair any damaged component(s).
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



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 line to verify that it is not obstructed.
Are the fuel lines free of debris or damage?

Yes


- Go To 6


No


- Replace the damaged or obstructed fuel injector supply line.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



6. DAMAGED OR OBSTRUCTED HIGH PRESSURE CONNECTOR
Remove the high pressure connector for the suspect cylinder.
Inspect both ends of the high pressure connectors for signs of damage.
Using shop air pressure, blow out the high pressure connector to verify that they are not obstructed.
Are the high pressure connectors free of debris or damage?

Yes


- Go To 7


No


- Replace the damaged or obstructed high pressure connector.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



7. FUEL INJECTOR
Remove the suspect fuel injector.
Are the fuel injectors damaged?

Yes


- Replace the external damaged fuel injector & high pressure connector.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 8



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 injectors & high pressure connectors?

Yes


- Replace the internal damaged fuel injector and high pressure connector.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 9



9. INTERNAL ENGINE DAMAGE
Perform engine compression test.Component Tests and General Diagnostics
Did the suspect cylinders pass the compression test?

Yes


- Go To 10


No


- Repair the internal damage to the engine.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



10. INTERNAL ENGINE DAMAGE
Perform engine leak down test.Component Tests and General Diagnostics
Did the suspect cylinders pass the leak down test?

Yes


- Test Complete.


No


- Repair the internal damage to the engine.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test