Automatic Stability Control (asc) problems of the 2007 Lexus ES350

I purchased a new 2007 lexux Es350 on April 12, 2007. In a right hand turn, the vehicle severely oversteered. Immediately the check engine light came on, with an error message to check vsc. As a result I returned the vehicle to the smithtown Lexus service department on Apr. 19, 2007 with 244 miles on the odometer. They took over twenty-four hours to diagnose the fault. They allege that the failure is the result of a defective sensor in the transmission. Although I have requested corroboration of the cause from a Lexus factory representative and confirmation of the inability to obtain a replacement part for a week, and inspection of the defective part as removed from the vehicle none of these requests have been met as of April 25, 2007. As the defect is a safety related issue of vehicle stability I am concerned that the car poses a potential safety hazard to the public.