ON CERTAIN 4X4 VEHICLES, AN IMPROPERLY HEAT TREATED UPPER CONTROL ARM ATTACHMENT BOLTS MAY BREAK RESULTING IN SEPARATION OF THE UPPER CONTROL ARM. THIS COULD CAUSE LOSS OF VEHICLE CONTROL AND A POSSIBLE CRASH. CORRECTION: UPPER CONTROL ARM ATTACHING BOLTS WILL BE REPLACED WITH BOLTS THAT MEET THE HARDNESS SPECIFICATION.