Circuit DescriptionThe water-in-fuel sensor is attached to the fuel filter. The electronic 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 then 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. The OEM supplied fuel filter is located on the intake side of the engine.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault CodesThe ECM detects that the water-in-fuel sensor signal voltage is above 4.95-VDC for 1 second.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.Conditions for Clearing the Fault CodeTo validate the repair, 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 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.

Shop TalkPossible causes for this fault code include:

Open RETURN or SIGNAL circuit in the harness, connectors, or sensorSIGNAL wire shorted to sensor supply or battery voltage.Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Possible Cause:1) Engine Harness2) ECM calibration