Check Gauges Indicator
WARNING: This page is about a different car, the 1994 Pontiac Grand Am. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect ECM connector C3. Disconnect fuel pump switch/oil pressure sender connector. Turn ignition on. If CHECK GAUGES indicator is on, check Dark Green wire for a short to ground. If wire is okay, replace IPC. If check gauges indicator does not light, problem is engine performance related. See appropriate G - TEST W/CODES article in ENGINE PERFORMANCE.