Circuit/System Verification

Ignition ON/vehicle in Service Mode, radio ON.
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 (UZ6 without IOR) , or Speaker Malfunction (UQA) , or Speaker Malfunction (IOR)
- Go to next step: If audio is heard clearly
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
All OK.