Fuel Pump Monitor (FPM)
FPM circuit is spliced into the Power-To-Pump circuit and used by the PCM for diagnostic purposes. The PCM sources a low current voltage down the FPM circuit.
With the fuel pump off, voltage is pulled low by the path to ground through the fuel pump. With the fuel pump off and the FPM circuit low, the PCM can verify that FPM circuit and Power-To-Pump circuit are complete from the FPM splice through the fuel pump to ground.
With the fuel pump on, voltage is supplied from the CCRM to the Power-To-Pump and FPM circuits. With the fuel pump on and FPM circuit high, PCM can verify that Power-To-Pump circuit from CCRM to FPM splice is complete. It can also verify that fuel pump relay contacts are closed and battery voltage is supplied to CCRM for the relay. See CCRM circuit schematic in CIRCUIT TEST X in appropriate G -TESTS W/CODES - EEC-V article in the ENGINE PERFORMANCE section for more information.