Begin the system diagnosis with Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information:
| • | The identification of the control modules which commands the system | 
| • | The ability of the control modules to communicate through the serial data circuit | 
| • | 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.