GM Service Manual Online
For 1990-2009 cars only

Begin the system diagnosis with Diagnostic System Check - Theft Deterrent . The Diagnostic System Check provides the following information:

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

The Diagnostic System Check identifies the correct procedure for diagnosing the system, and identifies the procedure location.