DTC 53

Battery - Ignition/Fuel Reference Voltage Input Circuit:

CIRCUIT DESCRIPTION
The PCM monitors the ignition fuel reference voltage on circuit 480. If the ignition is "ON", the engine speed is over 800 rpm, and the PCM reads the ignition fuel reference voltage over 17.1 volts, Code 53 will set.

TEST DESCRIPTION

Code 53 Diagnostic Chart:

Numbers below refer to circled numbers on diagnostic chart.
1. Battery/charging system voltage should be between 10.0 and 17.0 volts (with a fully charged battery, system voltage with the engine running is normally 13.5 - 14.5 volts.)
2. Checks to see if the indicated high system voltage is due to the PCM mis-reading the voltage, or if voltage is really that high.
3. Checks to see if voltage regulator in alternator fails when the system is under heavy electrical load. If voltage is greater than 17.1 volts, alternator is charging, but voltage is not regulated. Repair or replace alternator.