Engine Control Module: Service and Repair

Computer:

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, CALPACK, and if equipped, the MEMCAL must be removed from the Computer being replaced and transferred to the new unit. Refer to PROM, CALPACK and 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. Right hand hush panel.
3. Electrical connectors from the ECM.
4. ECM mounting bracket.
5. ECM from the passenger compartment.
6. ECM access cover.
7. MEM-CAL and/or CALPAK.
8. New ECM from its packaging and check the service number to make sure it is the same as the defective ECM.

INSTALL OR CONNECT:

1. The MEM-CAL and/or CALPAK in the socket.
CAUTION: Press only on the ends of the MEM-CAL and/or CALPAK. Small notches in the MEM-CAL and/or CALPAK must be aligned with the small notches in the socket. Press on the ends of the MEM-CAL and/or CALPAK until the retaining clips snap into the ends of the MEM-CAL and/or CALPAK. DO NOT press on the middle of the MEM-CAL and/or CALPAK, only on the ends.
2. Access cover on the ECM.
3. ECM in the passenger compartment.
4. ECM mounting hardware.
5. Electrical connectors to the ECM.
6. Right side hush panel.
7. Negative battery cable.

FUNCTIONAL CHECK:

ALDL Connector (Located Underdash):

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 41,42,43,51, or 55 occur, or if the "SERVICE ENGINE SOON" light is on consistently with no codes, the MEM-CAL is not seated properly or is defective.
4. Before starting engine perform IDLE LEARN PROCEDURE. Refer to ADJUSTMENT PROCEDURES/IDLE LEARN PROCEDURE.