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Home >> Oldsmobile >> 1991 >> Calais L4-151 2.5L >> Repair and Diagnosis >> Powertrain Management >> Relays and Modules - Powertrain Management >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Service and Repair >> Engine Control Module (ECM) Replacement
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Engine Control Module (ECM) Replacement

ECM Location - Behind RH Side Of Instrument Panel:




ECM And PROM Access Cover:




Prom Removal And Tool:








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 must be removed from the ECM being replaced and transferred to the new unit. Some ECM's are equipped with another chip called a Cal-Pak. If the ECM if equipped with a Cal-Pak chip, it will be located next to the PROM and must be transferred along with the PROM.

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.