Originally Posted by JCL

I spend some time following the threads at e90post in the forced induction forum. It makes for good reading. Some of the periodic BMW software updates added 'tuner detection codes' for lack of a better phrase, flags that mark that a tune was installed. Tuners responsed by providing a tool that clears them, as well as CEL faults. More and more detection methods will keep coming, and tuners will keep trying to figure out how to beat them. The stakes are rising for manufacturers, and they won't just sit and watch it. They will manage their warranty exposure. Recently a BMW customer went in for maintenance, and had his tune detected. He was surprised, as he had cleared all codes immediately prior to visiting the dealer. Turns out that the OBD goes through a reset after clearing codes, and the catalytic converter readiness flag takes up to 50 miles to reset, depending on temperature. So, they caught him for having recently cleared codes. Pretty funny, actually. In his case, the dealer didn't report him to BMW and flag his warranty, they called him and told him to come get his car before they did that. They gave him a break. I think they were making a point.

All of the history is in the DME/DDE, and can always be pulled out. For some data, it takes the factory to do that instead of the dealer, but it is always possible. Some tuners are claiming that if you don't let them take out your box and send it to the factory, it can't be detected. In my business whenever we had field follow (new test) units, we linked them up to the factory remotely for troubleshooting and flash upgrades. I don't see why BMW wouldn't have the same capability.