2021 TOYOTA PRIUS Vehicle Speed Control Problems

The contact owns a 2021 Toyota Prius. The contact stated while driving approximately 35 - 45 MPH, the vehicle independently accelerated. The brake pedal was depressed but failed to stop the vehicle immediately. The contact swerved around the vehicle in front and ended up on the opposite side of the roadway. The contact attempted to avoid oncoming traffic and swerving around all the other vehicles and ended up in a ravine. The contact's husband depressed the START/STOP button from the passenger’s side to turn off the vehicle, enabling the vehicle to come to a stop. The contact restarted the vehicle and continued to drive the vehicle to the dealer at slow speeds. The dealer was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was made aware of the failure by the dealer. The failure mileage was 56,000.