GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Circuit/System Description

The instrument panel cluster (IPC) displays the engine speed based on the engine speed data from the body control module (BCM). The engine control module (ECM) sends the engine speed signal information via the serial data circuit to the BCM. The BCM sends a message to the IPC indicating the engine speed. The IPC displays the engine speed based on the serial data message from the BCM.

Reference Information

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Lifting and Jacking the Vehicle

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, with the scan tool, perform the IPC Gage Sweep Test in the IPC Output Controls. Verify that all gage dials move from minimum to the maximum value and back to the gage minimum value.

If the tachometer does not perform the IPC Gage Sweep Test, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for IPC replacement, setup, and programming