Buick Regal: OnStar Audio Malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Refer to Diagnostic Procedure Instructions for an overview of each diagnostic category.

Diagnostic Fault Information

1. No (or Noisy) OnStar Audio

Circuit/System Description

When an OnStar keypress is made, a serial data message is sent to the audio system to mute all radio functions and output OnStar 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

• Refer to OnStar/Telematics Wiring Schematics
• Refer to Radio/Navigation System Wiring Schematics (IOB) , Radio/Navigation System Wiring Schematics (IOR) or Radio/Navigation System Wiring Schematics (IO5/IO6) , or Radio/Navigation System Wiring Schematics (IOS/IOT)

Connector End View Reference

Component Connector End View Index

Description and Operation

OnStar Description and Operation (UE1 with IOB/IO6) , OnStar Description and Operation (UI3) , or OnStar Description and Operation (UE1 without IOB/IO6).

Electrical Information Reference

• Refer to Circuit Testing
• Refer to Connector Repairs
• Refer to Testing for Intermittent Conditions and Poor Connections
• Refer to Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

1. Ignition ON/vehicle in Service Mode, 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 (UQ3 without NKC), Speaker Malfunction (UQ3 with NKC), Speaker Malfunction (UQA with IO5/IO6), or Speaker Malfunction (UQA without IO5/IO6)

• Go to next step: If audio is heard clearly

3. Verify that the Connecting to OnStar message is heard clearly through the audio system when the OnStar blue button is pressed.

• If OnStar message is noisy or distorted

Refer to Circuit/System Testing

• Go to next step: If OnStar message is heard clearly

4. All OK.

Circuit/System Testing

1. Ignition OFF/vehicle OFF, and all vehicle systems OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON/vehicle in Service Mode.

2. Test for less than 4 V between each of the signal circuits listed below and ground:

• Terminal 1
• Terminal 2
• If 4 V or greater

1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON/vehicle in Service Mode.
2. Test for less than 1 V between the signal circuits and ground.
   • If greater than 1 V, repair the short to voltage on the circuit.
   • If less then 1 V, replace the A11 Radio.

• Go to next step: If less than 4 V

3. Ignition OFF/vehicle OFF.

4. Test for infinite resistance between each of the signal circuits listed below and ground:

• Terminal 1
• Terminal 2
• If less than infinite resistance

Repair the short to ground on the circuit.

• Go to next step: If infinite resistance

5. Disconnect the X1 harness connector at the A11 Radio.

6. Test for less than 2 Ω in each of the signal circuits listed below end to end:

• K73 Telematics Communication Interface Control Module Terminal 1 X2
• K73 Telematics Communication Interface Control Module Terminal 2 X2
• If 2 Ω or greater

Repair the open/high resistance on the circuit.

• Go to next step: If less than 2 Ω

7. Replace the K73 Telematics Communication Interface Control Module.

8. Verify that the Connecting to OnStar message is heard clearly through the audio system when the OnStar blue button is pressed.

• If audio is not heard clearly

Replace the A11 Radio.

• Go to next step: If audio is heard clearly

9. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio or telematics communication interface control module replacement, programming, and setup.

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