Fuel Pump Relay: Description and Operation
FUEL PUMP RELAY - PCM OUTPUTThe fuel pump relay is located in the Fuse/Relay Block.
The fuel pump relay supplies battery voltage to the fuel pump. A buss bar in the Fuse Block supplies voltage to the solenoid side of the relay, while a buss bar in the Fuse/Relay Block supplies voltage to the contact side of the relay. The fuel pump relay power circuit contains a fuse between the buss bar in the Fuse/Relay Block and the relay. Refer to the Wiring Diagrams for circuit information.
The PCM controls the fuel pump relay by switching the ground path for the solenoid side of the relay ON and OFF. The PCM turns the ground path OFF when the ignition switch is in the OFF position. When the ignition switch is in the ON position, the PCM energizes the fuel pump. If the crankshaft position sensor does not detect engine rotation, the PCM de-energizes the relay after approximately one second.