Begin the diagnosis by reviewing the system Description and Operation, reviewing the Description and Operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the Description and Operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Vehicle Access in order to identify the correct procedure for diagnosing the system and where the procedure is located.
For all vehicle access systems, begin the system diagnosis with the Diagnostic System Check - Vehicle. The Diagnostic System Check - Vehicle will provide the following information:
| • | The identification of the control modules which command the system |
| • | The ability of the control modules 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.
