Car Slowed Down On Its Own Problems of Toyota Prius

Every once in a while - it can be months between events - our Prius momentarily slams on the brakes when driving at highway speeds while nothing else is going on. We know it's not operator error. It's happened to my wife several times and me once. When it happened to me I was driving straight ahead on a dry, lightly traveled divided highway during the day. Everything on the dashboard lights up, alarms go off, the car decelerates like I suddenly stomped on the brake pedal though my foot never moved off of the gas, it lasts for maybe a second and then the car is back to normal. It's the same each time it's happened. Luckily each time this has happened we haven't had anyone tailgating us. We've taken it to the dealer multiple times. The first couple of times they looked at us like we were loony. They checked it out and we got it back with a message that said the technician checked the computer and test drove it for 20 miles and the car was operating as designed. Except it happened again. We finally convinced them that this was maybe a legitimate issue and they said they brought in a Toyota field specialist who checked the car out and they said that the issue was the pcs wave radar sensor that was slightly out of alignment due to body damage (my wife had hit a small deer about a year prior to that - damage was minor and repaired at a local body shop). After they realigned the sensor, the car behaved itself for about five months. Until yesterday when it happened again.

See all problems of the 2011 Toyota Prius 🔎.