B2455

CIRCUIT DESCRIPTION
The Vehicle Communication Interface Module detects that the Cellular Microphone is connected through the Cellular Microphone Signal circuit and the drain wire.

CONDITIONS FOR SETTING THE DTC
- The ignition must be in the RUN or ACC position.
- The system voltage is at least 9.5 volts and no more than 15.5 volts.
- All the above conditions are present for greater than 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The Vehicle Communication Interface Module will not receive any signal from the microphone.
- Calls can be placed but the caller cannot be heard.
- The OnStar(R) status LED turns RED.

CONDITIONS FOR CLEARING THE DTC
- The Vehicle Communication Interface Module detects the microphone connected for 5 consecutive 100 millisecond cycles.
- A history DTC dears after 50 malfunction free ignition cycles.
- The Vehicle Communication Interface Module receives the clear DTC command from the scan tool.

TEST DESCRIPTION

Steps 1-9:

The number below refers to the step number on the diagnostic table.
2. This step checks that the Vehicle Communication Interface Module is sending out the proper supply voltage.