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 are not communicating
    â€¢ The identification of any stored DTCs and their status

The use of the Diagnostic System Check - Vehicle will identify the correct procedures to begin vehicle diagnosis. These must be performed before system DTC or symptom diagnosis.