Its the DSC button right down by the lighter. Eather they turned it on and unplugged the switch or they did some programming on it so you dont have the option of turning it on or off.
Anyway what happened to your x5? Did your check engine light come on and you had to get it towed? If your talking about an o-ring it could be as simle as the o-ring used to seal the intake somehow is leaking. That cound cause a check engine light and your car might run rough from it.