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.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

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

Special Tools

J 39916-A CD and Cassette Diagnostic Audio Kit.

Circuit/System Verification

  1. Tune to a strong AM or FM station and verify each speaker is producing clear and even sound, with no distortion.
  2. If any speaker is not producing sound or the sound produced is distorted, refer to Speakers Inoperative - One or More.
  3. Clean the tape head path using J 39916-A CD and Cassette Diagnostic Audio Kit.
  4. Play a cassette and listen for a incorrect speed or poor sound quality.
  5. If the radio plays the cassette poory, replace the radio.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Radio replacement, setup, and programming