For 1990-2009 cars only
Begin the system diagnosis with the HVAC Systems Diagnostic System Check. The Diagnostic 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 Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
