Self-Diagnostic System: Notes

WARNING: This page is about a different car, the 1998 Buick Riviera. However, it is still accessible from the selected car via links, so may be relevant.

Instrument Panel Cluster (IPC) is equipped with a self-diagnostic system, which detects system Diagnostic Trouble Codes (DTCs) or abnormalities. When a malfunction occurs, IPC will store a DTC. See DIAGNOSTIC TROUBLE CODES . Malfunctions are recorded as history/intermittent failures or as current failures. Current DTCs indicate IPC has detected a fault which is currently present. A history DTC indicates that Body Control Module (BCM) has previously detected a malfunction that is not currently present as it is either an intermittent condition or the system is not being currently operated.

A scan tool can be used to retrieve and clear DTCs. The scan tool also has several features that can be used to help locate an intermittent condition. When scan tool is used for system tests, it will display values actually seen or commanded by various systems (i.e., BCM, PCM).