My previous MY 2006 E90 used the vehicles stability system to monitor tire pressure by detecting slight differences in rotational speed. The European cars still use this method.
Essentially, what happens is the cars computer is reset (coded) to work off the European version simply by changing a setting the the cars computer. Then you simply unplug the antenna module in the right rear of the trunk and hit the "learn"/reset button on the Idrive or steering column stalk.
I picked up a nail in my E90 & my wife's X3 picked up two nails in both instances the Euro version preformed as advertised. The warning light came on in time to limp to a dealer for a replacement. The E90 had run flats & the X3 ran Michelin Pilot Sports.
Hope this helps
