According to reports in an Apple Discussions thread and in a separate but similar thread on the PriusChat forums, a number of iPhone and iPod touch users are suffering from in-car USB audio playback issues after the installation of iOS 4.1.
Affected users report hearing “scratching” or “crackling” noises when playing back music from an iOS 4.1 device over a vehicle’s built-in USB interface, with one Ford Fusion owner likening the effect to listening to a “scratched CD.” The problem does not appear to be limited to any one brand or major manufacturer, and several users have noted that audio playback via the headphone port or Bluetooth works fine.
Notably, one user claims that unpairing his Bluetooth connection allowed audio to play over USB without issue, suggesting the problem may be related to having Bluetooth on and or paired while attempting playback.
