GM Service Manual Online
For 1990-2009 cars only

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

    â€¢ The identification of the control modules which commands the system
    â€¢ The ability of the control modules to communicate through the serial data circuit
    â€¢ The identification of any stored diagnostic trouble codes (DTC) and their status

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