DTC P0178: WATER IN FUEL TEMPERATURE SENSOR TOO LOW
Monitor & Set Conditions
Water-In-Fuel (WIF) sensor circuit is monitored with ignition on. DTC will set if low WIF signal circuit voltage is detected at Engine Control Module (ECM).
Possible Causes
- Other DTC Present - P1488
- Other DTC Present - P0562
- WIF Sensor Signal Circuit Shorted To Ground
- WIF Sensor Signal Circuit Shorted To Sensor Ground
- WIF Sensor
- ECM
Testing
1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for engine DTCs. If DTC P1488 exists, perform DTC P1488: AUXILIARY 5 VOLT OUTPUT TOO LOW test. If DTC P1488 does not exist, go to next step.
2. If DTC P0562 exists, perform DTC P0562: CHARGING SYSTEM VOLTAGE TOO LOW test. If DTC P0562 does not exist, go to next step.
3. Turn ignition off. Disconnect WIF sensor harness connector. WIF sensor is located at the bottom of fuel filter/water separator on driver's side of the engine, just behind fuel injection pump. Disconnect ECM harness connector. ECM is located on driver's side of the engine, just in front of fuel transfer pump and contains a 50- pin connector. Using DVOM, measure resistance between ground and terminal "B" (Dark Green/Red wire) on WIF sensor harness connector. If resistance is 100 ohms or greater, go to next step. If resistance is less than 100 ohms, repair short to ground in Dark Green/Red wire between WIF sensor and ECM.
4. Ensure ignition is off. Ensure WIF sensor harness connector and ECM harness connector are still disconnected. Using DVOM, measure resistance between terminals "A" (Black/Light Blue wire) and "B" (Dark Green/Red wire) on WIF sensor connector. If resistance is 100 ohms or greater, go to next step. If resistance is less than 100 ohms, repair short between Black/Light Blue wire and Dark Green/Red wire between ECM and WIF sensor.
5. Ensure ignition is off. Reconnect ECM harness connector. Ensure WIF sensor connector is still disconnected. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal "B" (Dark Green/Red wire) on WIF sensor harness connector. If the voltage is not 4.5-5.5 volts, replace and program the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If the voltage is 4.5-5.5 volts, replace WIF sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.