I have a yukon XL. Over the winter months, I've recieved an error message telling me to get my 4x4 serviced and it will auto boot me to the 2wd mode. I've taken the yukon into the dealership, but each time they find nothing. Just wondering if anyone is having similar problems. Also now my traction control is doing the same thing. I have not taken it in yet. For both problem, after I have driven the yukon to my distination and leave the suv alone for a few hours the error messages will go away and everything would go back to normal.