CODE 53 - SYSTEM OVER VOLTAGE (2.5L)
This code indicates a basic alternator problem. Code 53 will be set if voltage at ECM terminal "B1" is greater than 17.1 volts for 2 seconds. Check and repair charging system.
Status of fuel pump circuit No. 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 No. 120 for at least 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 "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 an extended crank time, and the code will help in the diagnosis of "ENGINE CRANKS BUT WILL NOT RUN" condition.
If a fault is detected during start-up, the "SERVICE ENGINE SOON" light will stay on until the ignition is cycled off.
Code 54, Fuel Pump Circuit Flow Chart (Low Voltage). Scheme 79
Disconnect Fuel Module If Equipped. On Two Fuel Tank System
Check Pump Operation In Each Tank
