Powertrain Controls - ECM/PCM

PCM Power And Ground Circuits And IPC:

CIRCUIT DESCRIPTION
This diagnostic test monitors the Powertrain Control Module's (PCM)keep alive memory for a loss or unintended change of data. If such a condition occurs, DTC ECM Code 52 or DTC TCM Code 109 will set.

DTC 52/109 WILL SET WHEN
- PCM loss of prime power, such as battery.
- PCM loss of long-term memory with ignition "OFF."
- PCM engine running loss of long term memory.
- PCM intermittent loss of prime power.

ACTION TAKEN (PCM WILL DEFAULT TO)
DTC 52/109 does not illuminate the Malfunction Indicator Lamp (MIL) (Service Engine Soon).

DTC 52/109 WILL CLEAR WHEN
The fault no longer exists and the ignition switch is cycled "OFF" and "ON."

DIAGNOSTIC AIDS
DTC 52/109 can be caused by a loss of power or ground to the PCM. Check for dirty, damaged, loose connections or harness, backed out terminals at the PCM that could cause an open or short of prime power supply.

DTCs 52 AND 109 indicate that the "long term" memory in the PCM has been reset.

This will be the case whenever battery power is removed from the PCM (i.e., disconnecting battery cables, disconnecting PCM connector, etc.). this DTC should be "cleared" from memory after restoring the PCM's power supply.

If DTCs 52/109 are accompanied by complaint of engine quit, stumble, MIL's flashing, or other stored DTCs, check for an intermittent loss of power (CKT 1642) or ground (CKT 251) to the PCM. Manipulate wiring and connections with the engine running, remove and reinstall the PCM connectors and ensure that they are latched properly.