Just a quick suggestion to try and fix the CD..take a cloth and a small amount of "peanut butter" and rub it in a circular motion all over the disk. Clean the disk throughly to remove any left over so the CD is now free of any peanut butter.

Insert the cd in the nav to see if it now works. Thes cd's get fine scratches and for what ever reason, peanut butter seems to remove them from CD's. Try a small amount before spending $200 on a new cd.

If you do end up buying a new disk, make a back up of the disk to reburn if the issue happens in the future.

 

I had the same problem. The dealer replaced the disk & it still kept happening. They couldn't find the problem so they ended up replacing the whole navigation system. If it's not under warranty you will have to buy it at around $500.00 which sucks.... At that point you're better off going aftermarket.....