Diagnostic Aids
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Engine will not start if a total malfunction of Class 2 serial data circuit occurs when engine is not running. If total malfunction of Class 2 serial data circuit occurs while engine is running, PCM will operate in fail-enable mode and allow continued operation of vehicle. A short to ground/voltage or an internal module fault that shorts Class 2 data line to ground or voltage will cause a failure of all Class 2 communication. Modules are connected to Class 2 serial data circuit in a looped series, so an open in Class 2 serial data circuit between two modules will not cause a total malfunction of Class 2 serial data circuit.