Toyota Sienna sudden acceleration problems

Filed Jul 11, 2026 · Transmission · CA

I, as well as other owners of 2017–2018 Toyota Highlanders and 2017–2018 Siennas are experiencing serious transmission issues—including high-pitched whining, erratic shifting, clunks, hesitation, and premature failure. My 2017 Toyota Sienna has the UA80 8-speed automatic transmission at issue and started whining upon acceleration in March/April 2026 timeframe. It has always had the clunking and hesitation problem. According to Gears Magazine, the issue stems from a flawed assembly process involving the counter drive gear support. A locking tab meant to secure a vital retaining nut was not bent properly during factory assembly. This leads to gear movement, internal wear, whining, and eventually failure. Unknown to me, in 2019, Toyota had acknowledged the problem in Technical Service Bulletins T-SB-0160-18, T-SB-0008-21, which only go to dealers, and implemented a limited Customer Support Program (CSP ZJC)—but only offered coverage to a narrow group of VINs, not to all VINs for model years that have these transmissions. My car is experiencing these same symptoms. My Toyota Dealer confirmed this problem and recommended a transmission replacement for $11,000 including labor. They said my VIN was not included in the Customer Support Program. Driving with a failing transmission is highly dangerous. A bad transmission can cause sudden power loss causing the car to halt to a sudden stop, unintended acceleration, or my car might get stuck in neutral while driving. I could lose control or be unable to get to the shoulder on the highway, cause a rear-end collision, or get stuck in busy traffic. DESIRED OUTCOME REQUEST: My VIN should be covered under the Customer Support Program in the category of cars that are “less than 10 years old regardless of mileage” or a full recall of all VINs of these model years with these transmissions should be executed. Thank you.

Filed May 8, 2026 · Acceleration · 120,000 miles · OH

The contact owns a 2014 Toyota Sienna. The contact stated that while driving at various speeds the vehicle had experienced unintended acceleration. During the failure the driver forcely pressed the brake pedal to stop the vehicle. The contact indicated that the failure had once occurred while a transporting a Uber passenger. The cause of the failure was not determined. The manufacturer and local dealer were not contacted. The failure mileage was 120,000.

Filed Mar 12, 2024 · Acceleration · 200,000 miles · GA · 1 injury

The contact owns a 2004 Toyota Sienna. The contact stated that while driving approximately 65 MPH the vehicle suddenly experienced unintended acceleration and the speed of the vehicle increased to over 90 MPH. During the failure, the braking system had failed and would not stop the vehicle while pressing the brake pedal. The front passenger was able to view the fuel pedal was stuck to the floor and was able to physically pull the fuel pedal up from the stuck position and the vehicle's speed was reduced. The incident lasted for approximately 10 minutes. During the incident, the police were on the scene. A police report was later filed at the scene and the vehicle was towed to the local dealer. The contact was informed by the dealer that the failure was due to a missing fuel pedal pen. No further information was available. The manufacturer was notified of the failure. The contact expressed experiencing emotional stress and anxiety during and after the incident. The manufacturer was notified of the failure. The failure mileage was 200,000. The VIN was not available.

Filed May 11, 2023 · Acceleration · 45,750 miles · VA

The contact owns a 2019 Toyota Sienna. The contact stated that after he entered the vehicle, he depressed the brake pedal to start the vehicle. After the vehicle was started, he shifted into reverse(R) while the brake pedal remained depressed; however, the vehicle inadvertently accelerated without warning. In a desperate attempt to stop the vehicle from crashing into another vehicle, the contact shifted into drive(D) while the brake pedal remained depressed. The contact then stated that he applied pressure to the brake pedal to stop the vehicle from accelerating when the vehicle then jumped the curb and struck a garbage can. The contact then shifted into reverse(R) while the vehicle continued to accelerate to move away from the garbage can and then shifted in neutral(N). The contact then shifted back into park(P). The contact then stated that after he placed the vehicle in park, the inadvertent acceleration stopped. The contact shifted into drive(D) and the vehicle performed as designed; however, the contact was concerned for his safety and carefully drove the vehicle to his residence where the vehicle remained. The contact was unsure if any warning lights were illuminated. The vehicle was not diagnosed or repaired. Neither the dealer nor the manufacturer was notified of the failure. The failure mileage was approximately 45,750.

Filed Apr 7, 2023 · Acceleration, Engine · CA

Today 4/7/23 My 2017 Toyota Sienna accelerated on its own. I was driving my 4 children to school and we were at a stop light. When I took my foot of the brake to start making a turn the car gunned it around the corner. It scared everyone in the car half to death. Thankfully no one was hurt but it looks like others on here haven't been so lucky with this issue. I hope toyota does the right thing a d fixes this issue before more people die.

Filed Oct 19, 2021 · Engine, Fuel system · NV · crash

On 10/14/2021, as my wife was pulling into our attached garage, the vehicle suddenly accelerated, hitting a metal storage shelf located at the back wall of the garage. The impact of the crash caused the vehicle and the shelf to extensively damage the dry wall of that area of the garage, as well as to damage the pedestal supporting the house water heater, which resulted in the water heater detaching away from the wall and being destroyed. There was, of course, also major damage to the front bumper area of the vehicle. It is my contention that the cause of the accident lies in some component of the vehicle acceleration system. I believe this to be true because of two prior incidents which occurred within the month before this happened. On 09/16/2021, I was driving this vehicle and wanted to make a U-turn. I was traveling at approximately 10 MPH, but as I began the turn, suddenly, the vehicle accelerated to about 25 MPH, even though my foot was off the accelerator. My wife and granddaughter were in the vehicle at the time and both expressed alarm, somehow thinking I had purposely made this maneuver, which I assured them that I had not. Then, approximately 7-10 days later (I am unsure of the date), I was driving, alone, in this vehicle and went to make a left-hand turn. The vehicle again accelerated, even though I had removed my foot from the accelerator pedal and was applying the brakes. I estimate that as I began the turn, my speed was 10-15 MPH, but the vehicle accelerated to 25-30 MPH. I dismissed both of these prior incidents as not too important and attributed them to some unknown anomaly on the road. However, after the latest incident involving the damage to my garage and vehicle, research showed that several Toyota models and specifically the Sienna have had similar issues in the past. I am reporting this incident to Toyota for their evaluation, but wanted to make your agency aware, also.

Filed Oct 5, 2021 · Acceleration, Engine · FL

This is to advise you of a safety issue with our 2013 Toyota Sienna XLE Minivan having a V6 (3.5L) engine. Our vehicle currently has 118,169 miles on it and has been well maintained. This vehicle was purchased new and is operated primarily in Florida where we live. Over the last 6 - 10 months on three occasions our Sienna Minivan suddenly lurched forward as the engine revved up. On all three occasions, I had to take quick action and with significant force press the brake pedal as well as place the minivan in neutral and then into park in order to stop our minivan from surging forward and hitting the car in front of me. On all three occasions, my right foot was on the brake pedal when this occurred and on two of the three occasions, our minivan was slowly accelerating from either a stopped position or a very low speed (5 mph or less). On one of the occasions I was approaching an intersection with a stop sign and our minivan was decelerating to a stop when the engine revved up and the minivan surged forward. This occurred as our minivan was going approximately 5 - 10 mph. There were no warning lamps, messages, or other symptoms prior to any of these incidents. I have reported this condition to our local Toyota Dealer but they said they could not duplicate the issue during their test drive. This is a serious safety condition and one that could result in a serious accident with injuries particularly if the driver is not quick to react to this unexpected condition.

Filed Dec 16, 2020 · Acceleration · 173,000 miles · CA

The van has sudden acceleration problem at times it is hard to slow it down even stop it. The problem mainly occurs from stop and go especially if it has been parked for few hours.

Filed Dec 16, 2020 · Fuel system · 4,000 miles · CA

Tl* the contact owns a 2020 toyota sienna. The contact stated that while driving at various speeds, the vehicle intermittently jerked and lunge forward while the accelerator pedal was depressed. There was no warning. The contact then received notification of the federal safety agency campaign number: 20v682000 (fuel system, gasoline) however, the part to do the recall repair was not yet available. Victory toyota (5 heitzinger plaza, seaside, ca 93955, (831) 393-3020) was contacted and it was confirmed that parts were not yet available. The manufacturer was made aware of the issue. The failure mileage was approximately 4,000. Vin tool confirms parts not available.*dt

Filed Jul 6, 2020 · Acceleration · 70,000 miles · IL

3 times this year, when slowing to a stop with my foot on the brake, the car suddenly accelerated, requiring me to apply as much brake pedal pressure as I could, as well as shifting to neutral to stop the car. This has occurred once when coming up to a stop sign, and twice while pulling into a parking space. Both times when pulling into the parking space, I was barely able to stop in time, almost hitting a car in the space in front of me. After the last time this occurred (7/3/2020), the car was taken to st. Charles toyota on 7/6, where they found nothing wrong with the vehicle. This started just this year; the vehicle has approx. 70,000 miles on it. We have owned the vehicle since new - it did not do this for the first 4.5 years of service.