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 powertrain control module (PCM) monitors the cruise control indicator switch. When the cruise on/off switch is switched ON, the cruise control switch is closed and the signal circuit is high. When the cruise on/off switch is switched OFF, the cruise control switch is open and the signal circuit is low.

Reference Information

Schematic Reference

    •  Cruise Control Schematics
    •  Engine Controls Schematics
    •  Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

Powertrain Control Module Connector End Views

Electrical Information Reference

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

Electrical Information Reference

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

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Ignition ON, install a scan tool and command the cruise control indicator ON. Observe the cruise control indicator in the instrument panel cluster (IPC).

If the indicator is illuminated, replace the PCM.
If the indicator is not illuminated, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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