when mine went it made my vehicle go into trans fail safe mode from time to time. it seemed to happen when mine got warmed up. when i would first start up and take off everything seemed fine however after a short trip, about 15 miles home it acted up, like i said after it had warmed up. strangely enough at the same stop light every day until i pulled the unit, sent it off and had it refurbished. after that no problems.