Powertrain Controls - ECM/PCM

DTC 54 Fuel Pump Circuit (Low Voltage):

Fuel Pump System Wiring Circuit:

CIRCUIT DESCRIPTION:
When the ignition switch is turned "ON," the Powertrain Control Module (PCM) will activate the fuel pump relay and run the in-tank fuel pump. The fuel pump will operate as long as the engine is cranking or running, and the PCM is receiving ignition reference pulses, or oil pressure switch is closed.

If there are no reference pulses, the PCM will shut "OFF" the fuel pump within 2 seconds after key "ON."

Should the fuel pump relay, or the 12 volt relay drive from the PCM fail, the fuel pump will be run through an oil pressure switch backup circuit.

DTC 54 WILL SET WHEN:
PCM detects a voltage below 9 volts prior to engine cranking.

ACTION TAKEN (PCM WILL DEFAULT TO):
The oil pressure switch will provide a current path for the fuel pump when oil pressure becomes great enough to close the contacts. The MIL will become illuminated.

DTC 54 WILL CLEAR WHEN:
A current DTC 54 will clear when voltage at the PCM is sensed within the calibrated voltage threshold. A history DTC 54 will clear after 50 consecutive ignition key cycles without a current DTC 54 being stored.

DIAGNOSTIC AIDS:
An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold or engine oil pressure is low. The extended crank period is caused by the time necessary for oil pressure to build enough to close the oil pressure switch and turn "ON" the fuel pump.