Fuel Pump Monitor (Without Fuel Pump Driver Module)

The Fuel Pump Monitor (FPM) circuit is spliced into Fuel Pump Power (FP PWR) circuit and is used by PCM for diagnostic purposes. PCM sources a low current voltage down FPM circuit. With fuel pump off, voltage is pulled low by path to ground through fuel pump. With fuel pump off and FPM circuit low, PCM can verify FPM and FP PWR circuits are complete from FPM splice through fuel pump to ground. This also confirms that FP PWR or FPM circuits are not shorted to power.

With fuel pump on, voltage is supplied from fuel pump relay to FP PWR and FPM circuits. With 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.