Engine Control Module: Service and Repair

Service of the ECM should normally consist of either replacement of the ECM or a MEM-CAL change. If the diagnostic procedures call for the ECM to be replaced, the Memory-Calibration unit (MEM-CAL) and ECM should be checked first to see if they are the correct parts. Also, perform the ECM Replacement Check, CHART C-1, before replacing the ECM to assure that the replacement ECM will not be damaged.

When replacing a production ECM with a service ECM, transfer the broadcast code and production number from the production unit to the service unit. Also, during replacement, the PROM, and the MEM-CAL must be removed from the ECM being replaced and transferred to the new unit.

1. Disconnect battery ground cable.
2. Then disconnect two computer electrical connectors.
3. Remove computer mounting hardware.
4. Remove computer from passenger compartment.
5. Reverse procedure to install.