P1222 - Leak Detection During Motoring

NOTE: For a complete wiring diagram, refer to the Wiring Information. 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.

**A solid Wait to Start lamp will illuminate in the cluster along with chiming 10 times. When the fault goes inactive, it will clear the wait to start lamp with no chimes**.

When Monitored:

• Engine is motoring and at operating temperature with no fuel system and engine speed related DTC's.

Set Condition:

• Counter reaches a calibrated value.

Possible Causes

• EXCESSIVE INJECTOR RETURN

NOTE: Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

OTHER DTC's PRESENT

1. Turn the ignition on.

2. With the scan tool, select View DTC's. Are there any other fuel system related DTC's present along with this DTC?

a. Yes >>> Perform the diagnostics for the other fuel system DTC's before proceeding.

b. No >>>> Perform the INJECTOR RETURN FLOW TEST procedure.