Ya know, I was getting the BAS/ESP light, intermittently and like you describe, about 2 weeks after I got my Xfire and I searched the forums here for an answer. I let it go on because I tested the systems by doing some hard braking (checking the Braking Assist System) and looking for the system to add some additional braking force: It worked as far as I could tell, and then I checked out the ESP (Electronic Stability Program) by putting the car through some exceptionally hard turns and I felt the brakes kick in to not allow the car to go into a slide so I think that worked. I hooked up a OBDII reader (port is just forward of the hood release) to the car (long cable on it taped to the underside of the dash while driving) to try to pull some codes and I got nothing. I think the car has to get used to your driving habits, strange as it seems. A couple weeks more driving after that and I haven't got a BAS/ESP light since. I don't like to say it, and I sure don't want to be wrong since it involves your stopping ability but drive it like you like for a while and I'll bet you quit seeing the light. If you still get the light and your stopping ability seems compromised, go see the dealer and get the codes (if any). If you get codes, please post them here, there are real experts on this forum that can interpret them better than me...Good luck with your problem and I hope it goes away by its self like mine did...