Powertrain Controls - ECM/PCM

DTC 54 (PCM):

Fuel Pump Relay Circuit (93PCM6):

CIRCUIT DESCRIPTION
The status of the fuel pump circuit 120 is monitored by the Powertrain Control Module (PCM) at terminal "B12" and is used to compensate fuel delivery based on system voltage. This signal is also used to store a Diagnostic Trouble Code (DTC) 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 120 for at least 2 seconds after the ignition is turned "ON," or any time reference pulses are being received by the PCM.

DTC 54 will set if the voltage at "B12" is less than 2 volts for 1.5 seconds since the last reference pulse was received. This DTC is designed to detect a faulty relay, causing extended crank time, and the DTC will help diagnose an engine that "Cranks But Will Not Run."
If a fault is detected during start-up, the "Service Engine Soon" light will stay "ON" until the ignition is cycled "OFF."

DIAGNOSTIC AIDS
Refer to "Intermittents", - Intermittent Malfunctions.