Powertrain Controls - ECM/PCM

DTC 53 Chart:

System Voltage Circuit:

Circuit Description:
The PCM has the ability to determine if the ignition feed circuit has more than 16.5 volts applied to it. This feature is to protect the PCM circuitry as well as components that have voltage applied to them by the PCM. The circuit that is monitored for an over voltage condition is CKT 439 (ignition feed).

DTC 53 Will Set When:
The ignition is "ON" and the PCM is sensing greater than 16.5 volts at PCM terminal "C3" for 10 seconds.

Action Taken (PCM will default to):
The MIL will become illuminated and all PCM outputs will be disengaged. The transmission will default to 3rd gear and have maximum line pressure.

DTC 53 Will Clear When:
A current DTC 53 will clear when battery voltage is sensed below 16.5 volts. A history DTC 53 will clear after 50 consecutive ignition key cycles without a current DTC 53 being stored.

Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. Normal battery output is between 10 - 16.5 volts.

2. Checks to see if the high voltage reading is due to the generator or PCM. With engine running, check voltage at the battery with a DVM. If the voltage is above 12.1 volts, the PCM is OK.

3. Checks to see if generator is faulty under load condition.