If there is water in the fuel system, the water in fuel sensor switch will close and produce a low voltage on the signal circuit. When the engine control module (ECM) detects a low signal from the water in fuel sensor the ECM will send a serial data message to the instrument panel cluster (IPC). The IPC will then illuminate the WATER IN FUEL message in the driver information center (DIC).

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

1. Ignition OFF, disconnect the harness connector at the water in fuel sensor.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit and ground.

⇒	If greater than 1.0 ohm, test the ground circuit for an open/high resistance.

3. Install a 3-amp fused jumper wire between the signal circuit and ground. Verify the scan tool Water In Fuel Sensor parameter is Water.

⇒	If not Water, test the signal circuit of the water in fuel sensor for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

4. If all circuits test normal, test or replace the water in fuel sensor

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.