Owner-reported complaints naming the brake system, filed with NHTSA
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Reports naming service brakes, the antilock braking system, brake hoses, master cylinders or the parking brake. Every record below is an owner-reported complaint about the 2021 Toyota Redundant Sienna submitted to NHTSA — not a confirmed defect, not a recall and not a manufacturer bulletin. 80 reports on file name it.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
The 25 most recent of 80, in the owner's own words
When braking to a stop at low speed (stopping at stop sign or at light), then car accelerates forward even though my foot is on the brake attempting to slow the car down. This unintended acceleration is dangerous and can cause an accident.
When braking downhill, the car will lurch forward causing me to have to break harder.
Brake Transition Issues: I have noted frequent jolts of power when braking, which creates at least the sensation of, if not actual acceleration while breaking. Web research suggests this may be linked to the vehicle switching between regenerative and mechanical braking systems, and that the problem is acute with 2021 and 2022 Toyota Siennas, which, if accurate, means Toyota has applied a fix to subsequent model years, but has not systematically addressed the first two years of the current Sienna generation.
Occasionally the brakes seem to stop working briefly, and the van even accelerates while the brakes are engaged. It happened again today but has happened since we got the van new in 2021. The dealer cannot replicate the problem. The problem is discussed on this thread: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
When braking, the brakes will unexpectedly slip. There is generally a loss of brake and a split-second surge that is rather like acceleration (since the car is no longer being slowed down by the brakes). This occurs unexpectedly, unpredictably and without any warning. Having the car suddenly move forwards without brakes is dangerous and could cause the car to hit a pedestrian or another car. This has also happened multiple times while angle parking which almost caused a collision. Two Toyota dealers and a Firestone Tire Center have been unable to replicate the braking issue and tell me that there is no problem with the braking system. I have had both of them inspect the car multiples times, and the issue continues to happen.
Car accelerating when braking especially at slow speed. This has happend many times and dealership not aware of a solution for this issue. This acceleration do not happen all the time but happens radmonly. Concerned about safety and hence reporting.
When slowing down the brakes work at first, but the slip and the vehicle rolls freely, then once you press them harder it engages and brakes. But for about 2 seconds there is no breaking! This has happened several times prior to today.
My van been giving me some weird issues lately. When I’m going downhill, my brakes don’t seem to work well! I have to push it all the way down, like a spongy. It doesn’t break until I put on the emergency brake. the seat broke only weighed 185 pounds! the wiper blades don’t do a great job cleaning the driver’s side after I bought new ones. Dealership wipers
When pulling into a shopping center parking space, my mother applied the brakes to slow down, but the vehicle seemed to surge and hit the car in front. It then surged again and pushed that car into another. No airbags deployed, and no one was injured, but someone could have been hurt either by the van itself or one of the other 2 vehicles. The dealer is scheduled to look at the vehicle, but stated on the phone that they "hadn't heard of this happening". There were no warning lights showing. My daughter stated that after the impact, she looked at my mother's feet, and her foot was clearly on the brake. I looked on the internet later, and found several threads of people complaining about their Toyota Sienna hybrids doing similar things.
I was driving home from the grocery store going roughly 40 mph. I turned into a turn lane going into our neighborhood and started to press the break. Instead of breaking my car accelorated. It happened quickly, maybe 2 seconds. But it was very concerning. A warning flashed on my dash board that said, "break accelorating." I continued to push the break and started to slow down.
Car lunges forward when braking. This occurs at low rates of speed and is particularly prone to occur when making right and left turns. This has been going on since I bought it in 2021. Dealer laughs at me
This problem has been happening for a while now, over one year. When I am braking there is a jolt of acceleration. This happens frequently, and I believe this is dangerous.
Unexpected sudden acceleration when braking at low speed
When applying the brakes, at lower speeds around 20 MPH my Sienna lunges forward for a few seconds, increasing speeds. This is happening frequently in school zones due to the slow speeds. Dealer told me it was out of warranty (36k or 3 yrs) and i had to pay $250 for diagnostic plus $300 for a TSB solfware reset because the Fed didn't receive enough complaints from users to make Toyota do a recall on this Safety issue. This is a major safety issue myself and many other Sienna owners are dealing with.
In certain conditions, like coasting downhill and lightly braking and then going to harder braking - there is an unintended lurch forward which requires immediate harder braking to stop the vehicle.
Car lurches forward a few feet while braking. Listed approximate start date but it happens intermittently.
When stop at the stop sign and step in the brake... the car momentary accelerates by its self. Its very dangerous. Pls fix the problems Toyota.
-Multiple instances recently of feeling like the car was accelerating or lurching forward lightly while I was braking - thought I was going crazy. Today however, the car very clearly lurched forward while I was braking coming into an intersection with my kids in the car. Checked my foot on the pedal, mats, etc. Will be taken to dealer on earliest appointment they have in 7 days. -If there was a car coming through that intersection, my family and I could have been T-boned due to the unexpected acceleration. -There are no warning lamps or messages active in the vehicle. -Symptoms likely started a few months ago, but the most severe instance was today, 9/16/2024. I finished driving my kids to soccer and while there I googled this and called my dealer. Apparently this is a known issue? -How can Toyota not notify owners of this serious issue? There needs to be a recall immediately. This is my family vehicle that we bought new just a few years ago, this is dangerous and absolutely unacceptable.
Intermittently and randomly the vehicle will lunge forward with the brake applied. I engage the brake, the vehicle slows and then lunges/lurches forward as if I were not braking. Not only is this terrifying but it is also extremely dangerous. This has happened many times since purchase in February 2021 and continues to now.
a "REPETITIVE" 2021 hybrid Sienna Limited accelerates *when my foot is definitely pressing lightly on the brakes*.
See attached document for complaint.
While braking, the brakes will momentarily stop working. This has happened multiple times. Today, it caused the van to not be able to stop in time and the van finally came to a stop in the middle of a four way intersection. I did a Google search. There are many many people in online forums who have reported this same issue.
Acceleration or surge seemingly while transitioning from regenerative braking to friction braking. Observed numerous instances where at slower speeds, after removing my foot from the accelerator and beginning brake application, a surge or acceleration occurs. In these instances I ensured that my foot was NOT contacting the brake and accelerator simultaneously. There is a distinguishable surge in driveline when this occurs. The surge may also be caused or exacerbated by a change in driveline power (engine/battery) occurring simultaneously with the transition from regenerative to friction braking. One of the most concerning instances of the anomaly occurred while turning. When making accelerating, coordinated turn and expecting the vehicle to respond appropriately by decreasing speed, it instead momentarily accelerated. This caused great concern and a moment of panic as I had to immediately react to avoid striking other vehicles or obstacles because my intended path of travel changed as a result of this surge. Since this report of surging of the Sienna Hybrid is also reported by other owners on various forums, I’m willing to have additional sensors installed to enable ample recording of these events. This should be considered a safety event.
The car accelerates during breaking
When applying light brake force to slow to stop for traffic light/sign the vehicle will feel like the brakes have released and stop slowing (feels like vehicle surges forward) requiring to either really apply much greater force to pedal or to release and reapply force to brake pedal to continue to slow the vehicle. Safety concern as without warning and not consistently happening additional 20 to 50 foot braking distance added to vehicle stop. Occurrence is random and happens approximately one in ten stops. The main consistency is a lower speed and gentle type stop: start braking speed generally in the 25-35mph range, brake release feel at 10-15mph range with light to medium braking force being applied. Seems to happen most often with a light downhill gradient. Occurs rendomly and cannot be reproduced on demand for service tech. Has happened since vehicle was bought new and still occurs randomly 26000 odo.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Categories with enough reports to have a page of their own
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