I have been to BMW 5 times because of navi. It works then all of the sudden starts driving me through water and gets me all off track. I try to set vehicle position but once it locates me and i start driving i'll be going one direction and it'll have me driving in another. Randomly after i park the car and maybe the next morning it will be working. Any ideas or thoughts. BMW is taking the hit for this one so i'm not that concerned but what is going on....

Have they checked the GPS antenna? Mine was bad a while ago and caused erratic GPS behavior.

not sure, they said they changed chip twice, and something about antenna. I'm dropping it off again monday. Not a bad deal as long as they keep it i get a loaner so it's costing them money, and all I want is my car to navigate me.