Sensor, Water In Fuel: Operation

The Water In Fuel (WIF) sensor sends an input to the Powertrain Control Module (PCM) when it senses water in the fuel filter/water separator. As the water level in the filter/separator increases, the resistance across the WIF sensor decreases. This decrease in resistance is sent as a signal to the PCM and compared to a high water standard value. Once the value reaches 30 to 40 kilo ohms, the PCM will activate the water-in-fuel warning lamp through CAN bus circuits. This all takes place when the ignition key is initially put in the ON position. The PCM continues to monitor the input while the engine is running.