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 PROM must be removed from the Computer being replaced and transferred to the new unit. Refer to PROM for replacement procedures.
WARNING: Before removing power to the ECM turn the ignition key "OFF," or damage to the ECM may result.
ECM Removal And Installation:
Prom Unit Socket:
Remove or Disconnect:
1. Negative battery cable
2. ECM mounting bolts
3. ECM connector shield
4. Connectors from ECM
5. ECM mounting hardware if ECM is being replaced
6. PROM access cover
7. PROM
MEM-CAL Or PROM Unit Installation:
Install or Connect:
CAUTION: Press down on the ends of the PROM socket until the clips are against the sides of the PROM. Small notches in the PROM must be aligned with the small notches in the controller board. DO NOT Press on the ends of the PROM until the retaining clips snap into the ends of the PROM. Press inward on the clips until they snap into place.
1. PROM
2. Access cover on the ECM
3. ECM mounting hardware if ECM was replaced
4. ECM electrical connectors
5. ECM connector shields
5. ECM mounting bolts
5. Negative battery cable
ALDL Or DLC Connector:
Functional Check:
1. Turn ignition "ON."
2. Enter DIAGNOSTIC MODE by jumpering terminals A to B on the data link connector. A DTC 12 should flash four times if no other codes are present. This indicates the PROM is installed correctly and the ECM is functioning.
3. If DTC 51 occurs, or if the "SERVICE ENGINE SOON" "MALFUNCTION INDICATOR" light is on consistently with no codes, the PROM is not seated properly or is defective.