Self-Diagnostic System: Notes

WARNING: Vehicles are equipped with Supplemental Inflatable Restraint (SIR) system. Before attempting any repairs involving steering column, instrument panel or related components, see SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article.

CAUTION: Electronic modules are sensitive to static electrical charges. Proper grounding of technician and workplace is essential to prevent damage.

CAUTION: When using scan tool, exit all scan tool tests before cycling ignition switch from OFF to RUN position unless scan tool instructions indicate otherwise. Follow all scan tool manufacturer's instructions, or diagnostic trouble codes (actual or false) may set, vehicle systems may malfunction or scan tool may malfunction.

NOTE: Diagnostic Trouble Code (DTC) tests are written specifically for use with GM Tech 2 scan tool. Generic scan tool can be used but may have limited functions. This article only covers the portion of those systems and DTC tests which relate to instrument panel cluster system diagnosis.

NOTE: For component locations, see COMPONENT LOCATIONS . For wiring circuit identification, see WIRING DIAGRAMS .

NOTE: Use adapter from Terminal Test Adapter Kit (J-35616-A) connected to DVOM when making all measurements.

Instrument Panel Cluster (IPC) is equipped with a self-diagnostic system, which detects system Diagnostic Trouble Codes (DTC) or abnormalities. When certain malfunctions occur, IPC will store a DTC. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . Malfunctions are recorded as current or history failures. Current DTCs indicate instrument panel cluster has detected a fault which currently exists (some codes will remain current until next ignition cycle even if fault no longer exists). A history DTC indicates that instrument panel cluster previously detected a malfunction that does not currently exist.

A scan tool can be used to retrieve and clear DTCs. Scan tool also has several features that can be used to help locate an intermittent condition. Scan tool will display input status and data values used. Scan tool can also cycle several gauges and warning indicators on and off. This feature can determine if IPC is able to cycle a gauge or indicator, regardless of inputs or any specific program instructions. When these tests are selected, scan tool displays only information on action that IPC is commanding (verify if operation was actually performed). Ensure IPC is able to control each gauge and indicator.