P0640 Diagnostic Issue on 1995 Buick Riviera with Supercharged Engine

Model: 1995 Buick Riviera Fault Code: P0640 Posted: 2005-12-27 21:21

I own a 1995 Buick Riviera equipped with a supercharged engine and am currently encountering a P0649 diagnostic trouble code. The scanner indicates the issue is related to the Quad Driver Module. I have already replaced the ECM (with the same PROM), but the P0640 code persists. Despite consulting various service manuals, I'm unable to locate information about this specific module or its position within the vehicle's electrical circuit. This has left me completely confused and seeking expert advice on how to proceed with diagnosis and repair.