GM Service Manual Online
For 1990-2009 cars only

Begin the system diagnosis with the Diagnostic System Check - Radio/Audio System . The Radio/Audio System Diagnostic System Check will provide the following information:

    • The identification of the control module(s) which command the system.
    • The ability of the control module(s) to communicate through the serial data circuit.
    • The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Radio/Audio System Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.