Supersedes Technical Service Bulletin Group 91 number 13-76 dated February 22, 2013. Call quality using the hands-free function is poor. Additionally, voice-activated functions may be restricted. The driver sounds muffled. The voice of the driver is quiet. The driver?s voice is accompanied by background interference. Voice-activated commands are not recognized. Various malfunctions can result from the normal airflow out of the center instrument panel vents that are directed upward at the microphones in the roof module, and can limit microphone sensitivity.