The 4s will not play music through my 2009 Subaru Impreza STi iPhone dock, it also will not work with a Logitech radio dock.
However it does charge ok on these devices and will play through a cheap generic boombox.
My old iPhone 4 with iOS5 works fine with both these devices.
This problem has been posted on other forums for the iP 4s does anyone have any information on whether this is a hardware or software problem?
I have already done a full reset and reloaded the device as a new device