Wow, the same EXACT thing happened to me yesterday. I did the same thing as you, turn off the car, turn it back on, nothing. Finally, at one point, a "sync" screen came up and it started doing some sort of update/reboot type of thing. Since that happened, things have been back to 100% excellent. I don't know how that happened or why, it just did. I hope this isn't a frequent occurence. I've only had this thing for a week.