OnStar Audio Malfunction
OnStar Audio Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
When an OnStar(R) keypress is made, a serial data message is sent to the audio system to mute all radio functions and output OnStar(R) originated audio. After the audio system is muted, the vehicle communication interface control module transmits signals to the audio system on the audio signal and audio common circuits.
Reference Information
Schematic Reference
* OnStar Schematics OnStar Schematics
* Radio/Navigation System Schematics Radio/Navigation System Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
OnStar Description and Operation OnStar
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Tune radio to a known good station and verify the audio is heard clearly through all speaker channels.
• If audio is not heard clearly, refer to Speaker Malfunction Speaker Malfunction.
2. Ignition ON, radio ON, set volume to comfortable level and press OnStar(R) Call Center button. Verify Connecting to OnStar(R) message is heard clearly through the audio system.
• If OnStar(R) message is noisy or distorted, refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the radio.
2. Disconnect the X2 harness connector at the vehicle communication interface control module.
3. Ignition ON, test for less than 1 V between the vehicle communication interface control module cellular telephone voice signal circuit terminal 1 X2 and ground.
• If not the specified value, test the cellular telephone voice signal circuit for a short to voltage.
4. Test for less than 1 V between the vehicle communication interface control module cellular telephone voice low reference circuit terminal 2 X2 and ground.
• If not the specified value, test the cellular telephone voice low reference circuit for a short to voltage.
5. Ignition OFF, test for infinite resistance between the vehicle communication interface control module cellular telephone voice signal circuit terminal 1 X2 and ground.
• If not the specified value, test the cellular telephone voice signal circuit for a short to ground.
6. Test for infinite resistance between the vehicle communication interface control module cellular telephone voice low reference circuit terminal 2 X2 and ground.
• If not the specified value, test the cellular telephone voice low reference circuit for a short to ground.
7. Test for less than 2 omhs between the vehicle communication interface control module cellular telephone voice signal circuit terminal 1 X2 and the radio terminal 20 X1.
• If not the specified value, test the cellular telephone voice signal circuit for a open/high resistance.
8. Test for less than 2 omhs between the vehicle communication interface control module cellular telephone voice low reference circuit terminal 2 X2 and the radio terminal 6 X1.
• If not the specified value, test the cellular telephone voice low reference circuit for a open/high resistance.
9. If all circuits test normal, replace the vehicle communication interface control module.
10. If all circuits test normal, replace the radio.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Module References Control Module References for radio or vehicle communication interface control module replacement, setup, and programming.