GM Service Manual Online
For 1990-2009 cars only

Begin the system diagnosis with Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check will provide the following information:

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

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