1994 Lumina 3.1 ECM replacement

[soxenme]

Car has intermittent rough idle....runs great at faster speeds. Took it to our local Chevy dealer they diagnosed it as a "faulty ECM" and wanted over $500 to fix it. I can order a rebuilt ECM for slightly over $100.

Temped to try this but a few questions first:

1. Where exactly is the ECM?

2. The part indicates "The PROM[s]/CALPACK must be transferred from the original module to the replacement module." it looks like it just plugs into the replacement - correct?

3. Is there any reprogramming needed once replaced?

Thanks in advance for your help.

[Blue Bowtie]

The PCM is in the RF corner of the engine compartment.



The MEMCAL is accessed through a cover on the side of the PCM. Be sure the PCM is not plugged in to the vehicle wire harnesses when exchanging the MEMCAL.

[soxenme]

Thanks for the diagram. Is there any programming or re-programming that needs to be done once its replaced?

Thanks again.

[Tech II]

If your ECM has a transferable PROM/Memcal, then no further programming is needed...

[soxenme]

Thank you. Very helpful!