For 1990-2009 cars

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

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

• | No DTCs are set.

• | The ability of the control module to communicate through serial data circuit

2. Review the system operation in order to familiarize yourself with the system functions. Refer to Radio/Audio System Description and Operation .

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the radio. Refer to Checking Aftermarket Accessories .

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

### Intermittent Conditions

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:

• | Audio System Troubleshooting Hints

• | Radio Poor Reception

• | Noise Compensated Volume Inoperative

• | Audio Distortion - One or More Speakers

• | Noise Compensated Volume Inoperative

• | Reduced Volume - One or More Speakers

• | Speakers Inoperative - One or More

• | Speakers Inoperative - All

For navigation related symptoms, refer to Symptoms - Navigation Systems .