Entertainment system loses contact with smartphone plugged into usb port. sometimes turning off and turning the audio system restores contact, sometimes turning the car off completely is required. unplugging and re-plugging the smartphone does not fix the problem. this occurred first months ago (don't recall when or at what mileage as it's not a safety or health problem), but has started to occur more frequently the last couple of weeks. the increasing frequency has increased the irritation factor. *tr