Powertrain Controls - ECM/PCM

Circuit Description
The status of the fuel pump CKT 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 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 CKT 120 for at least 2 seconds after the ignition is turned "ON," or any time reference pulses are being received by the ECM.
DTC 54 will set if the voltage at terminal "B2" is less than 2 volts for 1.5 seconds since the last reference pulse was received. This code is designed to detect a faulty relay, causing extended crank time, and the DTC 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."

Diagnostic Aids:

^ Refer to "ECM Intermittent Codes or Performance".