Powertrain Controls - ECM/PCM

Chart DTC 53 System Voltage High:

Circuit Trans System Voltage Low:

CIRCUIT DESCRIPTION
The Powertrain Control Module (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 over voltage condition is CKT 439 (ignition feed).

DTC 53 will set when: The engine speed is greater than 800 RPM and the PCM is sensing greater than 16.5 volts at PCM terminal "C3".

Action Taken (PCM will default to): The Malfunction Indicator Lamp (MIL) will become illuminated and all PCM outputs will be disengaged.

Diagnostic Trouble Code (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 8-16.5 volts.
2. Checks to see if the high voltage reading is due to the generator of the 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. If the voltage is above 16.5 volts, refer to Starting and Charging.