For 1990-2009 cars

### Test Description

The number below refers to the step number on the diagnostic table.

1. If the Remote Radio Audio Output (-) circuit is shorted to voltage the vehicle communication interface module (VCIM) has been damaged and requires replacement.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: OnStar Schematics Connector End View Reference: Cellular Communication Connector End Views DEFINITION: This procedure is for diagnosing problems during OnStar® audio following a button press from the OnStar® button assembly.
1 | Did you perform the Cellular Communication Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Cellular Communication
2 |

1. Turn ON he ignition, with the engine OFF.
2. Turn ON the radio.
3. Set volume to a comfortable level.
4. Press the OnStar® Center Call button.

Can the "Connecting to OnStar" message be heard playing through the audio system at all?

Go to Step 3

Go to Step 5

3 | Tune the radio to a known good station. Can the audio be heard through all speaker channels? | Go to Step 4 | Refer to Diagnostic Starting Point - Entertainment in Entertainment
4 | Test the remote radio audio output (-) circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 9
5 | Is any distortion heard? | Go to Step 7 | Go to Step 6
6 | Test the Remote Radio Left Audio Signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 7
7 | Test the remote radio left audio signal circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 8
8 | Test the remote radio audio output (-) circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9
9 | Inspect for poor connections at the harness connector of the vehicle communication interface module (VCIM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 10
10 | Important: Perform the OnStar® setup procedure. Replace the VCIM. Refer to Communication Interface Module Replacement . Did you complete the repair? | Go to Step 11 | --
11 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2