Clutch master cylinder failed causing the car to not be able to disengage clutch with pedal making it extremely dangerous to stop car or remove it from gear. future attempts to start car with on-star on the phone so they could run diagnostic check remotely failed. 3 attempts to start car and it would not start. towed to dealer and upon arrival towing company had asked for mileage of car. exactly like above i pushed start button to turn gauges on dash, this time car started and overpowered emergency brake because it was still in gear and it ran into tow truck nearly hitting tow driver and was inches from cutting his legs off. in no way should this car have been able to start in gear and i believe it wouldn't have, had the clutch master cylinder not failed at only 4600 miles. *tr