P1222

P1222-LEAK DETECTION DURING MOTORING


For a complete wiring diagram, refer to Diagrams/Electrical.


When engine is motoring (i.e. Engine is running, but requires no fuel injection) the only required fuel delivery to the rail is due to natural leakage in the system. The natural leakage depends directly on the rail pressure. A definite amount of fuel is required to overcome the natural leakage, for different fuel pressures. The Engine Control Module (ECM) sets Leakage Detected, when the fuel flow exceeds an expected value. When a leak is detected in the system, a counter is initiated. When the counter reaches a predetermined value a fault is set and engine derate is enabled. When the leak is not detected the counter counts down, and once the counter becomes zero the engine is set back to normal running conditions.


- When Monitored:
Engine is motoring and at operating temperature with no fuel system and engine speed related DTCs.

- Set Condition:
Counter reaches a calibrated value.

Possible Causes:

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure

OTHER DTCs PRESENT

1. Turn the ignition on.
2. With the scan tool, select View DTCs.

Are there any other fuel system related DTCs present along with this DTC?

Yes
- Perform the diagnostics for the other fuel system DTCs before proceeding.

No
- Perform the INJECTOR RETURN FLOW TEST procedure. Injector Return Flow Test