Engine Control Module: Service and Repair

ECM And Connector:

When replacing a production Computer with a service Computer, transfer the broadcast code and production number from the production unit to the service unit. Also during replacement, the MEMCAL must be removed from the Computer being replaced and transferred to the new unit. Refer to MEMCAL for replacement procedures.

WARNING: Before removing power to the ECM turn the ignition key "OFF," or damage to the ECM may result.

Remove or Disconnect:
1. Negative battery cable
2. ECM mounting hardware
3. ECM mounting bracket
4. ECM connector shield
5. Connectors from ECM
6. ECM
7. ECM access cover
8. MEM-CAL

MEM-CAL Or PROM Unit Installation:

Install or Connect:
CAUTION: Press down on the ends of the MEM-CAL socket until the clips are against the sides of the MEM-CAL. Small notches in the MEM-CAL must be aligned with the small notches in the controller board. DO NOT Press on the ends of the MEM-CAL until the retaining clips snap into the ends of the MEM-CAL. Press inward on the clips until they snap into place.

1. MEM-CAL
2. Access cover on the ECM
3. ECM
4. ECM electrical connectors
5. ECM mounting hardware
6. Negative battery cable

ALDL Or DLC Connector:

Functional Check:
1. Turn ignition "ON."
2. Enter DIAGNOSTIC MODE by jumpering terminals "A" to "B" with key "ON" engine "OFF." A code 12 should flash four times if no other codes are present. This indicates the MEM-CAL is installed correctly and the ECM is functioning.
3. If code 51 occurs, or if the "SERVICE ENGINE SOON" light is on consistently with no codes, the MEM-CAL is not seated properly or is defective.