GM Service Manual Online
For 1990-2009 cars only

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit/System Description

The radio generates the audible warning through the left front speaker. The radio receives audible warning requests via class 2 serial data from the body control module (BCM).

Reference Information

Schematic Reference

    •  Instrument Cluster Schematics
    •  Body Control System Schematics
    •  Radio/Navigation System Schematics

Connector End View Reference

    •  Displays and Gages Connector End Views
    •  Data Communication Connector End Views
    •  Entertainment/Communication Connector End Views

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 Testing

  1. Ignition ON, headlamp switch OFF, verify the scan tool Headlamp Switch parameter is Inactive.
  2. If not Inactive, test the headlamp input signal circuit for an open or short to voltage. If the circuit tests normal, replace the headlamp switch.
  3. Ignition ON, park lamp switch OFF, verify the scan tool Park Lamp Switch parameter is Inactive.
  4. If not Inactive, test the parklamp signal circuit for an open or short to voltage. If the circuit tests normal, replace the headlamp switch.
  5. Ignition OFF, key out of the ignition, verify the scan tool Key In Ignition Status parameter is Key Out.
  6. If not Key Out, test the key in ignition signal circuit for an open or short to voltage. If the circuit tests normal, replace the ignition switch.
  7. Ignition ON, doors closed, verify the scan tool Door Ajar Switch parameters are Inactive.
  8. If not Inactive, go to Courtesy Lamps Always On .
  9. Ignition ON, rear gate closed, verify the scan tool Liftgate Ajar Switch parameter and the Liftglass Ajar Switch parameter are Closed.
  10. If not Closed, go to Courtesy Lamps Always On .
  11. If all circuits test normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ignition and Start Switch Replacement
    •  Turn Signal Multifunction Switch Replacement
    •  Control Module References for BCM replacement, setup, and programming