Circuit Description
The WIF sensor is attached to the fuel filter. The WIF sensor sends a signal to the electronic
control module (ECM) when a set volume of water has accumulated in the fuel filter. The WIF
circuit contain two wires: A return ground (pin 20), and a signal wire (pin 40).
Component Location
The water-in-fuel sensor is installed in the fuel filter and is located on the side of the head
approximately midway on the engine.
Cummins ISB CM550 (1990-94) Fault Code: 422 PID: 111 SPN: 111 FMI: 2 Colant Level Sensor Circuit Coolant Level Sensor Circuit
Cummins ISB CM550 (1990-94) Fault Code: 418 PID: 97 SPN: 97 FMI: 0 Water-In-Fuel Sensor Circuit
Cummins ISB CM550 (1990-94) Fault Code: 415-SW PID: 100 SPN: 100 FMI: 1 Oil Pressure – Engine Protection With An Oil Pressure Switch
Cummins ISB CM550 (1990-94) Fault Code: 415-SN PID: 100 SPN: 100 FMI: 1 Oil Pressure – Engine Protection
Cummins ISB CM550 (1990-94) Fault Code: 391 PID: SID 017 SPN: 632 FMI: 11 Fuel Pump Relay Coil Supply Circuit
Cummins ISB CM550 (1990-94) Fault Code: 387 PID: SID 232 SPN: FMI: 1 Accelerator Position Sensor Circuit
