B2455

DTC B2455

CIRCUIT DESCRIPTION
The vehicle communication interface module (VCIM) detects that the cellular microphone is connected through the cellular microphone signal circuit and the cellular microphone low reference circuit.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2455 Cellular Phone Microphone Circuit Malfunction

CONDITIONS FOR RUNNING 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.

CONDITIONS FOR SETTING THE DTC
- The VCIM detects an open in the cellular microphone low reference circuit or a short to voltage in the cellular microphone signal circuit.
- The above conditions are present for greater than 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The VCIM 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 VCIM detects the microphone connected for 5 consecutive 100 millisecond cycles.
- A history DTC clears after 50 malfunction free ignition cycles.
- The VCIM 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 VCIM is sending out the proper supply voltage.