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 telematics 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 1-2 Shift Solenoid (SS) Valve (M30)
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. Ignition ON, radio ON.
2. Verify that audio is heard clearly through all speaker channels when tuning radio to a known good station.
• If audio is not heard clearly
Refer to Speaker Malfunction Speaker Malfunction
• If audio is heard clearly
3. Verify that the Connecting to OnStar(R) message is heard clearly through the audio system when the OnStar(R) blue button is pressed.
• If OnStar message is noisy or distorted
Refer to Circuit/System Testing
• If OnStar message is heard clearly
4. All OK.
Circuit/System Testing
1. Ignition OFF and vehicle systems OFF, disconnect the X1 harness connector at the A11 radio and disconnect the X2 harness connector at the K73 telematics communication interface control module, ignition ON.
2. Test for less than 1 V between the K73 telematics communication interface control module signal circuit terminal 1 and ground
• If 1 V or greater
Repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 1 V between the K73 telematics communication interface control module signal circuit terminal 2 and ground.
• If 1 V or greater
Repair the short to voltage on the circuit.
• If less than 1 V
4. Ignition OFF.
5. Test for infinite resistance between the K73 telematics communication interface control module signal circuit terminal 1 and ground
• If less than infinite resistance
Repair the short to ground on the circuit.
• If infinite resistance
6. Test for infinite resistance between the K73 telematics communication interface control module signal circuit terminal 2 and ground.
• If less than infinite resistance
Repair the short to ground on the circuit.
• If infinite resistance
7. Test for less than 2 omhs between the K73 telematics communication interface control module signal circuit terminal 1 and the A11 radio cellular telephone voice signal circuit terminal 20.
• If 2 omhs or greater
Repair the open/high resistance in the circuit.
• If less than 2 omhs
8. Test for less than 2 omhs between the K73 telematics communication interface control module signal circuit terminal 2 and the A11 radio audio signal circuit terminal 19.
• If 2 omhs or greater
Repair the open/high resistance in the circuit.
• If less than 2 omhs
9. Replace the K73 telematics communication interface control module.
10. Verify that the Connecting to OnStar(R) message is heard clearly through the audio system when the OnStar(R) blue button is pressed.
• If audio is not heard clearly
Replace the A11 radio.
• If audio is heard clearly
11. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair procedure.
Control Module References Control Module References for radio or telematics communication interface control module replacement, programming and setup.