Supersedes Technical Service Bulletin Group 91 number 13-75 dated February 7, 2013. Customer concern is that there is no sound (from all audio sources) when vehicle is operated above 6 to 10 mph. When the ignition is cycled and the vehicle is stationary, the audio will work until the vehicle is driven again. Only vehicles with Concert Radio (PR 8UQ) and standard sound system (PR 9VD) are affected.