I just replaced all my brake pads with
EBC greenstuff jobbies & fitted new wear sensors. I assumed that the wear indicator idiot light would go out when the new sensors were plugged in but I can tell you it doesn't.
Great I'm thinking, bloody BMW have frigged it so that you have to get a dealer/tool to re-set the light to discourage home servicing. Anyway, after a bit of searching I found the solution & there's nothing to it. Just turn the ignition to on so the gauge cluster all lights up & leave it there without starting the car. After about 40 seconds the light goes out & your done