My 02 X5 has an MK3 nav unit. When I insert the map or OS CD, it spits it out after a few seconds. The CDs don't have any scratches. I've even tried burning a new OS CD to see if it would work, but it had the same result. What could be the problem? Is it a bad laser? Can it be fixed?

If it can't be fixed easily, I may consider upgrading to an MK4. From what I've read on the forum, it should be an easy swap, correct? Where is the best place to find one for cheap?

Please let me know. Thanks for your help.