ESP inoperative error code , was up . did the steering lock to lock thing to reset it but it kept coming back as well as the run flat inoperative warning they seem to go hand in hand . got the wheel alignment done and pumped the tires up to 37psi and everything has been good. The faulty brake brake switch issue doesnt apply to this 2009 CLK , I believe the physical brake switch was done away with in previous years, I found out the hard way by bothering to look for it.