Begin the system diagnosis with the Powertrain On Board Diagnostic (OBD) System Check . The Powertrain On Board Diagnostic (OBD) System Check will provide the following information:
| • | The identification of the control module(s) which command the system. |
| • | The ability of the control module(s) to communicate through the serial data circuit. |
| • | The identification of any stored diagnostic trouble codes (DTCs) and their status. |
The use of the Powertrain On Board Diagnostic (OBD) System Check will identify the correct procedure for diagnosing the system and where the procedure is located.