Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Verify the OnStar® voice recognition is operating normally.
- If the OnStar® voice recognition is inoperative, refer to OnStar Microphone Inoperative - Caller Cannot Be Heard .
- Ignition OFF, disconnect the radio harness connector X1 and CIM harness connector X3.
- Test for less than 1 volt on the voice recognition audio signal circuit radio harness connector terminal 4 and ground.
- If greater than specified value, test the circuit for a short to voltage.
- Test for greater than 1 ohm between the voice recognition audio signal circuit radio harness connector terminal 4 and ground.
- If less than specified value, test the circuit for a short to ground.
- Test for less than 1 ohm between the voice recognition audio signal circuit radio harness connector terminal 4 and the voice recognition audio signal circuit CIM harness connector terminal 2.
- If greater than specified value, test the circuit for an open/high resistance.
- Test for less than 1 volt on the voice recognition audio low reference circuit radio harness connector terminal 5 and ground.
- If greater than specified value, test the circuit for a short to voltage..
- Test for greater than 1 ohm between the voice recognition audio low reference circuit radio harness connector terminal 5 and ground.
- If less than specified value, test the circuit for a short to ground.
- Test for less than 1 ohm between the voice recognition audio low reference circuit radio harness connector terminal 5 and the voice recognition audio low reference signal circuit CIM harness connector terminal 4.
- If greater than specified value, test the circuit for an open/high resistance.
- If all circuits test normal, replace the radio.