Fuel Pump Monitor (Models Without Fuel Pump Driver Module)

The Fuel Pump Monitor (FPM) circuit is spliced into the Fuel Pump Power (FP PWR) circuit and used by the PCM for diagnostic purposes. The PCM sources a low current voltage down the FPM circuit.

With fuel pump off, voltage is pulled low by the path to ground through the fuel pump. With fuel pump off and the FPM circuit low, the PCM can verify the FPM circuit and FP PWR circuit are complete from the FPM splice through the fuel pump to ground. This confirms that the FP PWR or FPM circuits are not shorted to power.

With the fuel pump on, voltage is supplied from the fuel pump relay to the FP PWR and FPM circuits. With the fuel pump on and FPM circuit high, PCM can verify FP PWR circuit from fuel pump relay to FPM splice is complete. It can also verify that fuel pump relay contacts are closed and battery voltage is supplied to fuel pump relay.