2024 TOYOTA SIENNA Service Brakes Problems

Looked online to see if other Sienna drivers had the same issue with the hybrid system. Brakes are accelerating a bit even when already pressing on the brakes. It has happened enough times to be concerning. We have not taken it to the dealearship as of yet but will be getting in touch soon , now that we know it's a known issue. No warnings from vehicle.

On rare occasions (about once every 500 miles), when uniformly applying force to the brake pedal, the deceleration suddenly ceases and the vehicle seems to jerk forward. To a passenger, it feels like the driver's foot slipped off the brake pedal, but the driver continued to provide the same uniform force to the brake pedal and lost all deceleration. Typically, the driver is startled and presses significantly harder on the brake pedal jerking all occupants forward. The brakes re-engage and continue the deceleration at a much higher rate. Toyota addressed this problem with TSB 4724 which involved reprogramming the brake actuator assembly. This corrected the problem for about 3 months, but it is now occurring again. When the car was taken to the Toyota dealer again, the technician stated that TSB 4724 was cancelled, he could not duplicate the action (even though he was told it only happened on rare occasions), and claimed that the "brakes function properly as they should." Fortunately these loss of braking incidents have only occurred on dry pavement so that the driver did not lose control of the car when slamming on the brakes to compensate for the loss of deceleration. Coming down a hill on a snow covered road could have caused the vehicle to slide into an oncoming lane. It is my speculation that there is a null spot that exists during certain circumstances which causes there to be a "gap" between when this hybrid vehicle transitions between the dynamic hybrid brake and the friction wheel brake. Both braking systems independently work fine, but the transition between them (on rare occasions) does not occur continuously. This causes the driver to experience an unexpected loss of braking which, under the right conditions, could cause the driver to loose control of the forward motion of the car. As an engineer, I feel it is unacceptable for a safety system (braking) to not properly operate 100% of the time! On a Toyota owner's site, others have seen the same.

Intermittent unexpected acceleration during braking. This has occurred while braking into a downhill as well as at low speeds when turning into a parking space. Additional braking is required to stop vehicle or maintain desired braking.

When going down hill while braking, the brakes will release causing the car to lurch forward and then they grab again. It’s intermittent and Toyota has a TSB on it but the dealership with not fix it because they can’t duplicate the problem. It can cause people to take their foot off and of the brake pedal and trying to apply it again. Which can cause someone to rear end another car.

In general the braking system on this vehicle is poor. The van does not seem to want to stop unless you apply a lot of pressure on the brake pedal. I have taken the vehicle to the dealership who explained to me that the braking operation is normal. I replied “so the poor brake design was intentional”. The dealer said the braking system takes a little while to get used to. I have contacted Toyota corporate 5 times to express my concern about the brakes. The customer service representatives say that they will pass my concerns along. I personally own 6 vehicles. The brakes on this Toyota are by far the worst. It is not even close. I do not feel like this vehicle is safe. This is a minivan that is used to move families around. I do not feel safe in this vehicle and most importantly I am worried every time my wife drives this vehicle that someone will slam on the brakes in front of her the van will not stop in time. Toyota is the world’s largest auto maker, they can and should produce a better braking system than what is available with this van. This is unacceptable with braking technology available at this time in automotive history. Their lack of response to my concerns in also disappointing. Thank you for hearing my concerns.

When decelerating either for a traffic light or otherwise at the slow speed when the break is applied before coming to a stop, the car accelarates and then I have to slam on the breaks. this is very dangerous

When I am rolling to a stop, or lightly pressing in the brakes, the car will occasionally jolt forward and I have to slam on the brakes. It is not every time but has happened many times since buying the car new. I brought it into the dealership and they could not replicate it, but it makes me so scared to drive. This could result in an accident or the hitting of a pedestrian. No warning lights.

Unexpected sudden acceleration when braking

The contact owned a 2024 Toyota Sienna Hybrid. The contact stated while driving at an undisclosed speed, the brake pedal was depressed, however, the vehicle failed to stop as intended. No warning lights were illuminated. The contact stated the vehicle was unstoppable. The contact stated the option was to crash into the three vehicles which were coming from the opposite direction or to crash into the pole to bring the vehicle to a stop and avoid injuring pedestrians. The paramedics and the Police department arrived at the scene of the crash. The contact's wife, who was the occupant of the front passenger's seat, was transported to the local hospital. The contact sustained bruises and an open wound which was continuing to heal. The contact's wife sustained bruises and bumps. The vehicle was towed to a local tow yard. The vehicle was condemned as a total loss. A police report was filed. The manufacturer was made aware of the failure. The manufacturer ordered an investigation of the black box. The investigation was completed, and the contact was provided a copy. The failure mileage was approximately 3,000.

Mileage: 3,000

When coming to a stop at a red light or a stop sign vehicle keeps surging forward. Something in the vehicle is releasing the brakes. Seems to be happening on a regular basis, but is still randomly happening, Every day. If you’re close enough to the vehicle in front of you, you will hit the vehicle

I was at a complete stop. There were no obstacles around me or oncoming. When I pressed the accelerator nothing happened for a full 3 seconds, until my vehicle jolted forward at an excessive speed. Brakes were not working.