For 1990-2009 cars only
Important: The following steps must be completed before using the symptom table.
- Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
- Review the system operation in order to familiarize yourself with the system functions. Refer to OnStar Description and Operation.
| • | There are no DTCs set. |
| • | The control modules can communicate via the serial data link. |
Visual/Physical Inspection
| • | Inspect for aftermarket devices which could affect the operation of the Radio/Audio System. Refer to Checking Aftermarket Accessories. |
| • | Inspect for easily accessible or visible system components for obvious damage or conditions which could cause the symptom. |
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:
