DCT is not an issue
While performing diagnostics, a technician may notice DTC B2455 stored as a history code in the vehicle communication interface module (VCIM) when there is no issue with the microphone.
If there is no current concern with the cellular phone microphone operation, disregard this DTC. The microphone operation may be verified by making a Blue Button OnStar call.
Do not attempt any vehicle repairs to correct this condition. Updating to the latest software update will eliminate the DTC concern. Do not replace the microphone or VCIM when DTC B2455 is stored as a history DTC.
This TSB applies to 2011 Buick, Chevy, Cadillac and GMC vehicles equipped with OnStar Generation 9.0.