DTC 54

Chart - Code 54 Fuel Pump Circuit (Low Voltage):

Fuel Pump Circuit (low Voltage):

CIRCUIT DESCRIPTION
The status of the fuel pump circuit 120 is monitored by the Electronic Control Module (ECM) at terminal "A20" 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, or any time references pulses are being received by the ECM. Code 54 will set, if the voltage at terminal "A20" is less than 4 volts for 0.4 seconds since the last reference pulse was received. This code is designed to detect a faulty relay, causing extended crank time, and the code will help the diagnosis of an engine that "Cranks But Will Not Run". Refer to Computers and Controls / System Diagnosis / Diagnostic Charts / Chart A4-3. Chart A4-3 Engine 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 "OFF". However, if the voltage is detected below 4 volts with the engine running, the light will only remain "ON" while the condition exists. Circuits 120 and 480 are routed from the ECM through a mini harness connector to the fuel pump relay. A faulty connection at terminals "B" and "J" at the black connector could cause a Code 54.