Applications Using a Fuel Pump Relay for Fuel Pump On/Off Control

The fuel pump (FP) is a PCM output signal used to control the electric fuel pump. With the electronic engine control (EEC) power relay contacts closed, vehicle power (VPWR) is sent to the coil of the fuel pump relay. For electric fuel pump operation, the PCM grounds the FP circuit, which is connected to the coil of the fuel pump relay. This energizes the coil and closes the contacts of the relay, sending B+ through the FP PWR circuit to the electric fuel pump. When the ignition key is turned on, the electric fuel pump runs for about one second and will be turned off by the PCM if engine rotation is not detected.