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 provides an overview of each diagnostic category.

Circuit/System Description

The instrument panel cluster (IPC) illuminates the cruise control engaged indicator based on serial data messages received from the engine control module (ECM). The indicator is commanded ON when the cruise control system is controlling vehicle speed, and turned OFF with the system disengaged.

Reference Information

Schematic Reference

    •  Cruise Control Schematics
    •  Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Cruise Control Description and Operation
    •  Indicator/Warning Message Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, with a scan tool perform the Lamp Test for the instrument panel cluster (IPC) and observe the cruise control indicator.

If the cruise control indicator illuminates during the test, replace the ECM.
If the cruise control indicator does not illuminates during the test or remains illuminated at all times, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM or IPC replacement, setup, and programming