Hmmm from what I've read, it sounds like traction control/ESP but maybe I'm just understanding wrong. As far as turning it off...traction control and ESP are ALWAYS on to some degree at low speeds. Holding it turns it mostly off but there are times when it will still kick in. And of course it goes back to partially off above 45 MPH I think. So like Adam said, only way to completely get rid of it is to rig up a switch like his. You should see what it's like turning off TC/ESP on my mom's ML320 CDI...the button does basically nothing at all to turn it off.