For 1990-2009 cars

Important: The following steps must be completed before using the symptom table.

1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:

• | There are no DTCs set.

• | The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to OnStar Description and Operation.

### 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:

• | OnStar Global Positioning System (GPS) Data Not Current or Inaccurate

• | OnStar Microphone Inoperative - Caller Cannot Be Heard

• | No (or Noisy) OnStar Audio

• | OnStar Button LED Inoperative

• | OnStar Call Center Remote Function Requests Inoperative

• | OnStar One or More Buttons Inoperative

• | Unable to Contact OnStar Call Center

• | OnStar Voice Recognition Inoperative