Code 54: Fuel Pump Volt Low
The ECM monitors fuel pump pressure switch circuit voltage for fuel system adjustments. This signal is also used to store a trouble code if the fuel pump relay is defective or fuel pump voltage is lost while the engine is running. There should be about 12 volts on circuit No. 120 for 2 seconds after the ignition is turned on, or any time reference pulses are being received by the ECM.
Code 54 will set if the voltage on circuit No. 120 is less than 2 volts for 1.5 seconds since the last reference pulse is cycled off. However, if the voltage detected is less than 2 volts with the engine running, the light will only remain on while the condition exists. If no fault is found, see INTERMITTENTS in TESTS W/O CODES article.