Powertrain Controls - ECM/PCM

Trouble Code 53 Chart:

PCM Voltage Circuit:

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 circuit 639 (ignition feed).

DIAGNOSTIC TROUBLE CODE (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" and "C4."

ACTION TAKEN (PCM) WILL DEFAULT TO
The Malfunction Indicator Lamp (MIL) will become illuminated and all PCM outputs will be disengaged.

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
Numbers below refer to circled numbers 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 DVOM. 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, repair the generator.