Fuel Pump Monitor (FPM) - Single Speed MRFS

WARNING: This page does not describe the selected car, but rather 25 other vehicles, including the 2013 Lincoln Navigator, 2013 Lincoln MKZ, 2013 Lincoln MKX, 2013 Lincoln MKT, and 2013 Lincoln MKS. However, it is still accessible from the selected car via links, so may be relevant.

The FPM circuit is spliced into the FPPWR circuit and is used by the PCM for diagnostic purposes. The PCM sources a low current voltage down the FPM circuit. With the fuel pump OFF, this 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 the FPM and FPPWR circuits are complete from the FPM splice through the fuel pump to ground. This also confirms that the FPPWR or FPM circuits are not short to power. With the fuel pump ON, voltage is now being supplied from the fuel pump relay to the FPPWR and FPM circuits. With the fuel pump ON and the FPM circuit high, the PCM can verify the FPPWR circuit from the fuel pump relay to the FPM splice is complete. It can also verify the fuel pump relay contacts are closed and there is a B+ supply to the fuel pump relay.