DTC 54

Fig. 050 - WIRING DIAGRAM for Code 54 Fuel Pump Circuit (Low Voltage). VIN W:

CIRCUIT DESCRIPTION
The status of the fuel pump circuit 120 is monitored by the ECM at terminal B2 and is used to compensate fuel delivery based on system voltage. 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 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 at terminal B-2 is less than 2 volts for 1.5 seconds since the last reference pulse was received. This will help in detecting a faulty relay, causing extended crank time, and the code will help the diagnosis of an engine that "CRANKS BUT WILL NOT RUN".

If a fault is detected during start-up the "CHECK ENGINE" light will stay on until the ignition is cycled off. However, if the voltage is detected below 2 volts with the engine running the light will only remain on while the conditions exists.