Circuit DescriptionThe ECM uses diagnostic software to verify injector operation. During selected motoring conditions, each injector is fired. The fueling quantity and timing are then compared to a specified threshold. If fueling quantities are found to be above or below the specified threshold in two consecutive trips the malfunction indicator lamp (MIL) lamp is illuminated.

Component LocationThe injectors are installed in the cylinder head under the rocker lever cover.

Conditions for Running the DiagnosticsThe diagnostic runs for each injector during engine motoring at least one time per trip near the beginning of the trip or one time every 4 hours during a trip.

Conditions for Setting the Fault CodesThe ECM detects a fueling quantity error on two consecutive trips.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or the MIL when the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault CodeFor On-Board Diagnostic (OBD) engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes.The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop TalkThis fault code is intended to identify fueling quantity and timing issues.

In addition to injector over or under fueling, the following potential system defects trigger this fault code:

Fuel pressure sensor signal errors or noise (wire harness defects or damage)Self pumping (rail pressure rise during motoring)High drain line restriction (high drain line pressure)Debris in the fuel pump adapter passages (blocked air bleed orifice)Excessive high pressure fuel system leakage (rail pressure drops quickly after key-OFF).

Possible Cause:1) Fuel pump adapter and actuator failure2) ECM calibration