Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check - Vehicle in Vehicle DTC Information will provide the following information:
| • | The identification of the control module or modules that command the system. | 
| • | The ability of the control modules or modules to communicate through the serial data circuit. | 
| • | The identification of any stored diagnostic trouble code (DTCs) and the status of the codes. | 
The use of the Diagnostic System Check - Vehicle in Vehicle DTC Information will identify the correct procedure for diagnosing the system and where the procedure is located.