Schematic Reference

OnStar Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. Verify the OnStar® voice recognition is operating normally.

⇒	If the OnStar® voice recognition is inoperative, refer to OnStar Microphone Inoperative - Caller Cannot Be Heard.

2. Ignition OFF, disconnect the radio harness connector X1 and CIM harness connector X3.
3. 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.

4. 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.

5. 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.

6. 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..

7. 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.

8. 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.

9. If all circuits test normal, replace the radio.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for radio replacement, setup, and programming