Engine Control Module: Service and Repair

Computer Module:

EPROM Socket:

EPROM Installation:

POWERTRAIN CONTROL MODULE REPLACE
Service of the Powertrain Control Module (PCM) should normally consist of either replacement of the PCM or a Erasable Programable Read Only Memory (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.

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Right hand hush panel.
3. Connectors from PCM.
4. PCM mounting hardware.
5. PCM from passenger compartment.
6. PCM access cover.
7. EPROM.


NOTE:
To prevent possible Electrostatic Discharge (ESD) damage to the PCM or EPROM, do not touch the connector pins or soldered components on the circuit board and do not remove integrated circuit from carrier.

Using two fingers, push both retaining clips back away from the EPROM. At the same time, grasp it at both ends and lift it up out of the socket. Do not remove the cover of the EPROM. Use of unapproved EPROM removal methods may cause damage to the EPROM or socket.


IF PCM IS BEING REPLACED

Remove or Disconnect
1. New PCM from it's packaging and check the service number to make sure it is the same as the defective PCM.
2. Access cover.

Install or Connect
1. EPROM in EPROM socket.

CAUTION: Gently press down on the ends of the EPROM until the clips are against the sides of the EPROM. DO NOT press on the ends of the EPROM until the clips snap into place or the controller circuit board and/or clips may be damaged. Press inward on the clips until they snap into place.

2. Access cover on PCM.
3. PCM in passenger compartment.
4. Connectors to PCM.
5. Negative battery cable.