Operation CHARM: Car repair manuals for everyone.

Fuel Pump Relay: Description and Operation

Purpose:
To control fuel pump operation, a fuel pump relay is used.

Operation:
The PCM will supply power to the fuel pump relay controlling operation of the in-tank electric fuel pump. When the ignition switch is turned to the RUN position, the fuel pump relay activates the electric fuel pump for 1.5 to 2.0 seconds to prime the injector. If the PCM does not receive reference pulses from the crank position sensor and ignition module after this time, the PCM signals the relay to turn off the fuel pump. The relay will once again activate the fuel pump when the PCM receives reference pulses.