GM Service Manual Online
For 1990-2009 cars only

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:
  2. • There are no DTCs set.
    • The control modules can communicate via the serial data link.
  3. 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

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:

    •  Digital Radio Malfunction
    •  Radio Displays LOC, LOCKED, or CODE
    •  Radio Poor Reception
    •  Speaker Malfunction

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

For cellular communication related symptoms, refer to Symptoms - Cellular Communication.