Originally Posted by Vaheed1
No, there's no way of a dealer knowing. I would go as far as saying most dealerships will ignore ecu re-maps.
I wouldn't agree with the first statement because if the dealers want to find out if your car is mapped they will do so. A mapping company is not going to know more about the car than, obviously, what BMW know as they built it and can find changes performed to it if they wanted to. It is more common now for delearships to send diagnostics information to Germany for any queries or problems, more centralised control over vehicles rather than these dealers just choosing to issue and carry out, especially, warranty work.
Not meaning to scare anyone, but, dealer's can find out if the car has been tuned. However, the second part of the sentence, I wouldn't say generally they would ignore an ECU remap, but, they would look for a map probably as a last resort. It's just common sense, if they refuse work due to the remap that's your business gone from them, probably forever, and as far as they know potentially many others, for instance, if you post on forums.