Circuit DescriptionThe water-in-fuel sensor is attached to the fuel filter. The engine control module (ECM) provides a 5 volt reference signal to the water-in-fuel sensor. When the water collected in the fuel filter covers the sensor probes, the water-in-fuel sensor pulls the 5-VDC reference voltage to ground, indicating high water accumulation in the fuel filter.

Component LocationThe water-in-fuel sensor is integrated into the bottom of the OEM supplied suction fuel filter.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected water in fuel for an extended period of time.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.Conditions for Clearing the Fault CodeTo validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The ECM will turn off the amber CHECK ENGINE lamp immediately after 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 TalkWater in the fuel can do extensive damage to the fuel system, due to the tight tolerances of the fuel system components.

The fuel filter must be drained immediately.

If this fault code is active and there is no water in the fuel filter, a malfunctioning Water-In-Fuel sensor is a likely cause.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

Possible Cause:1) ECM calibration