Engine Control Module: Service and Repair

NOTE: Service of the ECM should normally consist of ECM or MEM-CAL replacement.


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 in this section for replacement procedures.

CAUTION:
^ To prevent internal ECM damage, the ignition must be OFF when disconnecting or reconnecting power to the ECM (for example, battery cable, ECM pigtail, ECM fuse, jumper cables, etc.).
^ To prevent possible Electrostatic Discharge damage to the PROM, CAL-PACK or MEM-CAL, DO NOT touch the component leads, and DO NOT remove the integrated circuit from the carrier.

REMOVAL:

1. Disconnect the negative battery cable.
2. Remove the glove compartment.
3. Disconnect the electrical connectors from the ECM.
4. Remove the ECM mounting hardware.
5. Remove the ECM from the passenger compartment.
6. Remove the access cover.
7. Carefully remove the MEM-CAL.
8. Remove the new ECM from its packaging and check the service number to make sure it is the same as the defective ECM.
9. Remove the access cover.

INSTALLATION:

1. Install the MEM-CAL in the MEM-CAL socket.
CAUTION: Press only on the ends of the MEM-CAL. Small notches in the MEM-CAL must be aligned with the small notches in the MEM-CAL socket. Press on the ends of the MEM-CAL until the retaining clips snap into the ends of the MEM-CAL. DO NOT press on the middle of the MEM-CAL, only on the ends.
2. Install the access cover on the ECM.
3. Install the ECM in the passenger compartment.
4. Connect the electrical connectors to the ECM.
5. Install the glove compartment.
6. Connect the negative battery cable.


FUNCTIONAL CHECK:

1. Turn the ignition ON.
2. Enter diagnostics.
a. Code 12 should flash four times (If no other codes are present). This indicates the MEM-CAL is installed properly and the ECM is functioning.
b. If Trouble Codes 41, 42, 43, or 51 occur, or if the "Service Engine Soon" light is ON constantly with no codes, the MEM-CAL is not fully seated or is defective.
^ If not fully seated, press firmly on the ends of the MEM-CAL.
^ If it is necessary to remove the MEM-CAL, follow the previous removal instructions.

NOTE: Before starting the engine, follow the "Idle Learn Procedure" as follows.
1. Install the Tech 1 "Scan" tool or equivalent.
2. Turn the ignition ON, with engine OFF.
3. Select IAC System, then Idle Learn in the Misc. Test mode.
4. Place the transaxle in PARK or NEUTRAL.
5. Proceed with Idle Learn as directed.