While driving my 2005 Cadillac Xlr on the interstate highway at approximately 70 mph, dry highway my car dipped to the left with instantaneous stabilitrack active flash. Then a few seconds later dipped left again and pulled severally to the left. The car was out of control. I could feel the ABS pulsating in the brake pedal. Fortunately nothing was in the lane next to me or there would have surely been an accident. I luckily was able to get the car back into my lane by just being fully aware of my surroundings and having both hands on the steering wheel at the time. A few seconds later another quick dip and the service stabilitrack came on. No further events. I called onstar for diagnostics and no trouble codes were found although the service stabilitrack was clearly illuminated. After a 5 minute stop (engine off/restart) the service stabilitrack did not back come on. After pulling on to the street (approximately 20 mph ) my left front wheel was completely locked - no release - no warning. Again dry highway, no potholes, clean street. With a car directly behind me, there was nothing I could do, but force the car forward. Rubber was burning and smoke coming from the completely locked left front wheel. One car nearly rear-ended me and then pulled up and ask what was wrong. He stated he saw no break lights but saw the car pull left and smoke from the front wheel. After forcing the car to the shoulder, I turned the car off. When it restarted the car the wheel was free and no warning lights. I drove the car into a parking lot and pulled the ABS fuse. I now have many warning lights, but know that the ABS and stabilitrack system is inactive. Steering position clip already replaced.

- Jupiter, FL, USA