general problems of the 2007 Mercedes Benz CLK350

I slowed down to make a turn and the car would not accelerate. It appeared to be stuck in high gear and did not shift back down to a low gear. This happened twice over a 3 week period. Both times I almost caused a traffic accident by being stuck in the middle of the road. I took the car to the mb dealer and was told it was the conductor plate sensor board that controls the transmission. The fix was $1300 to replace the unit.