2014 Toyota Prius Powertrain & Transmission Problems

Brake failure / Unintended Acceleration / Unknown cause Driving at approx 25mph on urban street (road in good condition no potholes, ramps, etc) I began to slowly brake as I approached a red traffic light. Instead of braking, the car began to accelerate quickly. I pressed the brake pedal again - no response. Pressed down hard for a third time which executed an emergency stop. This all happened within 1 or 2 secs. There were no injuries or involvement of other cars on this occasion. However, had I been any closer to the car in front, I believe I would have rear-ended it. Had this occurred a few moments later, at the busy junction 400m ahead, it could have been fatal. I am absolutely sure it was not driver error. I was not distracted, drive regularly, and have been a confident and safe driver for over 30yrs. I have never experienced this in a car before, and in fact wasn't aware that it could happen until I researched it on this site. No warning lights or indicators came on. The car ran normally for the remaining 2 miles back home. I didn't think anything of it before, but prior to this incident (in our 5 yrs ownership) there were approx. 5 instances when the engine would "roar" as if it wanted to accelerate but didn't when I was breaking or slowing down on a highway. Also, there were perhaps 3 instances when the car felt as though it was "running away" i.e. a slight acceleration - for no obvious reason. As neither of these represented safety issues, I assumed the car was just a bit old and these issues would be addressed as part of any service. Now I wonder if they are related to the sudden acceleration. The car is currently having a "health checks" run, but nothing has been found. I am reluctant to drive this vehicle if neither my dealer or Toyota can discern the problem. Overall we have been happy with this car and its performance, but this is an unacceptable "anomaly" as far as safety is concerned. Vehicle available for inspection.

CITY STREET ...PRESSED ON GAS AFTER THE LIGHT CHANGED AND IT DID NOT GO FORWARD AND THEN WAIVERED FOR AWHILE. I WAS VERY CLOSE TO HOME. I DO NOT KNOW HOW IT WILL WORK TOMORROW . NO WARNING LIGHTS WERE ON. IT HAS ACTED FUNNY BEFORE LIKE THIS ON HIGHWAY TRIPS AND THEN IT WOULDN'T DO IT. TOYOTA DEALERS DO NOT EVEN KNOW ABOUT THEM AND IT IS ANNOYING. IT FEELS LIKE A TRANSMISSION SLIPPING BUT HAS LESS THAN 70,000 MILES. I THOUGHT MAYBE HEAT IS DOING IT BUT NOW THAT IT IS OUT OF WARRANTY IE OVER 5 YEARS OLD, I DO NOT KNOW WHAT TO DO. I AM UNSURE WHAT CAUSES THIS SINCE NO LIGHTS WARN ANYTHING IS WRONG.

I PURCHASED THIS CAR USED, IN MAY 2017 WITH 14,500 MILES. I AM HAVING AN INTERMITTENT PROBLEM OF THE CAR SHIFTING BACK INTO REVERSE WHEN I AM TRYING TO SHIFT FROM REVERSE TO DRIVE. IT HAS HAPPENED APPROXIMATELY A DOZEN TIMES SINCE IN 5 WEEKS. I HAVE BROUGHT IT TO THE DEALERSHIP WHERE I PURCHASED THE CAR 3 TIMES. THEY ARE CURRENTLY KEEPING THE CAR OVERNIGHT. THEY HAVE NOT BEEN ABLE TO DUPLICATE THE PROBLEM, AS IT IS INTERMITTENT, AND DO NOT GET ANY CODES WHEN THEY'VE CHECKED THE CAR. THE ARE SUGGESTING IT IS A "DRIVER ERROR". IT DOES NOT SEEM TO MAKE A DIFFERENCE IF IT IS HOT OR COLD, ON A SLOPE OR FLAT SURFACE, OR IF THE CAR HAS BEEN SITTING IDLE FOR SOME TIME, OR HAVING BEEN DRIVEN A LONG DISTANCE. IT HAS HAPPENED IN EVERY SUCH SITUATION.

I PULLED OUT ON THE ROAD & THE IT DIED. IT A LITTLE BIT IT STARED UP. THE SAME THING HAPPENED LAST SUMMER. *TR

TL*THE CONTACT OWNS A 2014 PRIUS. THE CONTACT STATED THAT VEHICLE INTERMITTENTLY SHIFTED INTO NEUTRAL. THE CONTACT MENTIONED THAT THE DRIVE AND/OR REVERSE GEAR NEEDED TO BE HELD IN ORDER FOR THE GEAR NOT TO SHIFT INTO NEUTRAL. THE VEHICLE WAS TAKEN TO THE DEALER WHERE THE FAILURE WAS NOT DETERMINED. THE VEHICLE WAS NOT REPAIRED. THE VIN WAS NOT AVAILABLE. THE FAILURE MILEAGE WAS 20,000.

ACCELERATION DRIVING EAST ON US RTE. 50 AT ABOUT 60 MPH: VEHICLE ACCELERATED FOR NO APPARENT REASON. I NEARLY RAN INTO THE CAR AHEAD OF ME. THIS CAR IS EQUIPPED WITH RADAR ADAPTIVE CRUISE CONTROL, WHICH WAS ENGAGED AT THE TIME. I TURNED OFF THE CRUISE CONTROL IN TIME TO AVOID A COLLISION. UNINTENDED ACCELERATION HAS SPORADICALLY OCCURRED, BUT IT IS USUALLY FAIRLY MILD. THIS TIME IT WAS SO POWERFUL THAT IT FELT LIKE I HAD STOMPED ON THE ACCELERATOR; THE ENGINE ROARED AND THE CAR TOOK OFF AT FULL THROTTLE. THANKFULLY I WAS TRAVELING AT THE MAX DISTANCE OF THE CRUISE CONTROL. ACCELERATION WAS NOT CAUSED BY FLOOR MATS. I WATCHED WHILE THE DEALER SERVICE MANAGER CHECKED. DECELERATION DRIVING EAST ON I-70: THE CAR AHEAD OF ME SIGNALED TO EXIT THE INTERSTATE AND TURNED SMOOTHLY ONTO THE EXIT RAMP. AS SOON AS HE WAS OUT OF MY LANE MY CAR'S CRUISE CONTROL LOCKED ON TO THE THAT OF THE EXITING CAR AND VIGOROUSLY APPLIED THE BRAKES. STEPPING ON THE ACCELERATOR DID NO GOOD. *TR

TL* THE CONTACT OWNS A 2014 TOYOTA PRIUS. THE CONTACT STATED THAT THE VEHICLE WOULD REVERSE WHEN SHIFTED TO DRIVE WITHOUT WARNING. THE VEHICLE WAS NOT TAKEN TO A DEALER OR REPAIRED. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 3,000 AND THE CURRENT MILEAGE WAS 3,002.