Engine Control Module: Service and Repair

POWERTRAIN CONTROL MODULE REPLACEMENT
Service of the Powertrain Control Module (PCM) should normally consist of either replacement of the PCM or a EPROM change.

If the diagnostic procedures call for the PCM to be replaced, the engine calibrator (EPROM) and PCM should be checked first to see if they are correct. If they are, remove the EPROM from the faulty PCM and install it in the new service PCM. THE SERVICE PCM WILL NOT CONTAIN AN EPROM. Diagnostic Trouble Code (DTC) 51 indicates the EPROM is installed improperly or has malfunctioned. If DTC 51 is set, check the PCM connectors for bent pins or pins not fully seated in the socket. If it is installed correctly and DTC 51 is still displayed, replace the EPROM.

NOTE: When replacing the production PCM with a service PCM (controller), it is important to transfer the Broadcast code and production PCM number to the service PCM label. Please do not record on PCM cover. This will allow positive identification of PCM parts throughout the service life of the vehicle.

CAUTION To prevent internal PCM damage, the ignition must be "OFF" when disconnecting or reconnecting power to the PCM (for example, battery cable, PCM pigtail, PCM fuse, jumper cables, etc).

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Interior access panel.
3. Connectors from PCM.
4. PCM.
5. PCM access cover.
6. EPROM.

NOTE: To prevent possible Electrostatic Discharge (ESD) damage to the PCM, do Not touch the connector pins or soldered components on the circuit board.

INSTALL OR CONNECT
1. EPROM.
2. PCM access cover. Tighten access cover screws to 2-3 Nm (18-27 lb in).
3. PCM.
4. PCM connectors.
5. Interior access panel.
6. Negative battery cable.