2021 Toyota Redundant Sienna

While slowing to gentle stops for a STOP sign or a traffic light, occasionally the brakes will feel as if released and the vehicle stops decelerating in the expected fashion. This could result in a rear end collision with another vehicle if the operator doesn't rapidly apply firmer pressure to the brake pedal immediately. Because the brake pedal is already depressed, the forward collision avoidance system is overridden and will not stop the vehicle in time. This has occurred at random intervals and is quite disconcerting. I reported this to the authorized dealer's service manage, who said they were aware of the issue with the hybrid braking system, but that Toyota did not have a "fix" at this time. While reporting this issue at the dealer, another nearby customer began to relate the same issue with respect to his hybrid Toyota vehicle. The service representative did advise me to notify Toyota USA directly.

On 12/15/2023 I brought my 2021 Toyota Sienna, as described above, to Waites Toyota Dealership located in Watertown NY, because of a brake issue. Over the past month or so, when braking, we have experienced a jolt of power after decelerating despite keeping the brake pedal being depressed. A representative from Waites Toyota Service Department took the vehicle for a test drive and experienced the same issue and it was decided to take a further look at the brakes. The dealership contact TAS, a department within Toyota, and even though Toyota acknowledge there was an braking issue, Toyota did not have enough complaints concerning this issue, so no remedy was available. The vehicle has been converted so it can carry my daughter who is wheelchair bound, and has been for life. This is the only vehicle we have to transport her and even though we feel that this is a serious safety issue, we continue to use the vehicle as it is her only mode of transportation. The vehicle never displayed any warning lights or other symptoms, but the issue does happen almost every time you come to a stop. We feel Toyota should be forced to make this right. This vehicle cost more then $60,000 with the conversion and it should brake as it was designed to do.

While depressing the brakes, it will feel as though the brake "slips" for just a moment, and then re-engages. This causes the car to lurch forward, potentially colliding with a vehicle in front of you. This happens intermittently, and cannot be recreated on demand. It is, however, most noticeable when engaging the brakes downhill. The Toyota service department says that there is nothing wrong with the brakes, whatsoever. Numerous forums online would suggest otherwise. This seems to be an issue that a high number of Sienna hybrid owners are experiencing, and are being told by Toyota that the car's system says that there is nothing wrong. Consumers are being gaslit by Toyota, and are headed for serious safety issues if this is not addressed.

The contact owns a 2021 Toyota Sienna. The contact stated that while his wife was parking, she depressed the brake pedal however, the vehicle failed to stop. A message displayed on the instrument panel “Parking brake failure see dealer”. As a result, the vehicle crashed into a wall. The air bags failed to deploy. The contact’s wife sustained injury to her neck and shoulder. Medical attention was required. A police report was not filed. The vehicle was towed to the undisclosed dealer’s service center lot. The vehicle had not yet been diagnosed or repaired. The manufacturer was notified of the failure and the contact was advised to contact the NHTSA Hotline. The failure mileage was approximately 28,800. The contact stated that their vehicle continues to display the same message about the parking brake. They are unwilling to drive their vehicle.

Our 2021 Toyota Siena LE AWD has an issue with the brakes randomly releasing briefly when slowing to a stop. While slowing to a stop with steady pressure on the brake pedal, the braking action will momentarily give out, resulting in the vehicle lurching forward beyond the anticipated stopping/slowing distance before the braking action re-engages. This could easily result in a collision with cars, bikes, or pedestrians as the vehicle suddenly stops slowing without warning and unexpectedly increases stopping distance. It could result in a serious collision if the issue caused the Sienna's stopping distance to go past a stop sign or red light into an intersection. The problem is intermittent and difficult to reproduce, but has occurred repeatedly over the 2+ years we've owned the Sienna. Going over any kind of bump, crack, pothole, etc. seems to increase the likelihood of the occurrence, but it also happens on dry, flat pavement. No warning lamps, error messages, or other related symptoms from the vehicle either before or after occurrences of the problem.

The breaks give out to a point where you run the risk of running into someone or something. We've visited Toyota 3 times now complaining of this issue yet they just state it's the regenerative breaks and how they operate. Although the breaking never got to this level of safety concern until we reached around 30,000 miles. I filed a complaint with Toyota that resulted in nothing being done. A couple examples would be sitting at a stop light and the breaks release almost causing us to run into the car in front of us. Pulling into daycare trying to stop while pulling into the parking spot and the breaks release. The last one is while going down hills the breaks seem to let go and the vehicle speeds up. It scared my wife so much that we actually sold the vehicle as Toyota deemed it safe. We loved the vehicle but can't risk the safety of our family.

Since the day I bought the van new from a Toyota dealer, the brakes periodically (roughly once a week) will feel as if I've momentarily let off the brake and tapped the accelerator. In other words, the decelerating van suddenly has a quick surge forward or lunge of acceleration. It seems quite random when this happens. I'm usually applying a gentle to medium amount of braking and the van is traveling somewhere in the 5-35 mph range. I've yet to have any close calls, but it is a scary sensation (as if the brakes have momentarily given out) and I have to quickly react by pressing down harder on the brake pedal. Because it occurs quite randomly, I haven't taken the vehicle to the dealer yet as it is highly unlikely I'll be able to replicate the issue for them. I searched online and saw that hundreds of other Sienna 2021-23 drivers are reporting the same issue. To repeat: the problem has not been reproduced or confirmed by a dealer, nor inspected by the manufacturer, police, insurance rep or others. No warning lights come on when this issue happens. I currently have 36,000 miles on the vehicle. The issue has happened almost weekly since I first bought the vehicle.