They tell me that they do not want to start replacing parts unless they know which one it is. Apparently there is a sensor on left and right side. The cost is about 1200 bucks each plus labor. Now that the car is out of warranty I wonder if I am just SOL unless I pay for it. Doesn't happen all of the time, except when I am driving the car and the dealership is closed. Does not save the error in the computer. Shutting the car off and then on clears it till the next time it goes out.