Lemberg Law is investigating complaints regarding brake issues in the 2021 Toyota Sienna Hybrid. Vehicle owners report that the brakes sometimes feel soft, and their cars don’t seem to slow down.
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Many 2021 Toyota Sienna Hybrid owners are reporting that they have problems with the dual-braking systems in their minivans.
Toyota acknowledges in a technical service bulletin (TSB) issued on February 1, 2021, that there is a problem with the Sienna Hybrid’s brakes. But it does not address the transition pr
oblem resulting from the van’s friction and regenerative hybrid system brakes.
The condition the TSB describes is “an abnormal brake feel” that they describe as “a longer than usual brake pedal stroke. This may occur when the engine is off for more than five minutes after entering the vehicle and closing all doors before driving. The condition does not affect braking performance and will improve as the system performs learning cycles during vehicle operation. However, once the engine is turned off and the brake ECU goes to sleep, these learned values will be reset and the abnormal brake pedal feel will return.”
Discussions and complaints on the Sienna Chat forum about 2021 Toyota Sienna Hybrid brake issues started in September 2021 and haven’t stopped since. There are currently 29 participants in one group, many of whom have safety concerns. A second group, which discussed a “possible acceleration while braking issue,” had 18 participants. The issues are the same.
Additionally, owners of 2022 Sienna Hybrids say in the forum that they have the same problems.
A typical description of what happens is that the car doesn’t feel as if it is slowing down when the driver brakes. There is generally a loss of brake and a split-second surge that some say is rather like acceleration. Another description is a “mush at first, then grab” feeling, which drivers find dangerous.
An explanation is that when switching from hydraulic to regenerative braking, drivers feel as if their brakes have failed for a brief moment. A forum member explains this is “because at the brake crossover point there actually isn’t a strictly linear relationship between the pedal travel and the braking effort when the switchover between the braking systems happens.”
Many others comment on the malfunction, stating that the transition “should be seamless and instantaneous.”
The general consensus is that if there weren’t a problem with the dual-braking system, the transition would definitely be relatively seamless.
Although there is one complaint on file with the National Highway Traffic Safety Administration (NHTSA), it is about an unrelated issue. Forum members have been encouraged to complain to the NHTSA. “If there are enough reports, they will start an investigation and get Toyota to take corrective action if a widespread defect is found.”
But right now, dealerships aren’t helping.
One of the issues is that the surge, or brake transition, cannot be easily replicated. Also, driver experiences are inconsistent. For instance, some owners have no problems for weeks and then there are two surges in a single day.
Most Toyota dealerships are unable to replicate this brake problem and end up trying to reassure Sienna Hybrid owners that their vehicles are 100% okay. But owners who have experienced (and continue to experience) the problem are 100% unconvinced. Here are five examples:
”I mentioned (the brake problem) to the dealership, but the service technician told me he never heard of the issue and said he would check it out.” When he went to collect the car, they told him “everything is perfect and (they) can’t find any issue, of course.”
Another member said he’d brought up the issue with the mechanic “at my first maintenance. He said there was no thread on this and they found nothing wrong with the brakes. I’ve seen, and read, many threads, and blogs on this issue. I can’t understand how they have no records of this as frightening and dangerous this is.”
“I’ve been having this issue as well and (am) almost sure it’s when I’m soft braking and (I) release the brakes just a tiny bit. It happens more often when driving downhill. It’s been happening more often these days and my brakes are at 25%. I’m at 33K miles and will be replacing my brake pads soon. I mentioned this to the dealer on my 10k and 20k service but they can’t seem to replicate the issue and say the brakes are fine.”
Some dealers blame drivers for using both feet when they use their brakes.
“Our dealer was able to pull data showing that 4 times in April the brakes and accelerator were activated at the same time. I swear I don’t drive with two feet and I’m not making that mistake. It’s very frustrating. I feel like sooner than later this issue is going to cause me to get into an accident. I love my van, but this is unacceptable.”
“Having this issue and it’s really scary! Dealership is trying to say that I am driving two-footed, and I’m not.”
Some dealers do know about the problem, but they say nothing is wrong.
A forum entry made on July 12, 2022 states that a Toyota service manager maintains the brake problems are “not a defect.” And he agrees, though he is convinced that the design is dangerous.
“It is the transition between regenerative braking and mechanical braking that is temporarily interrupted by the uneven road surface. While it definitely feels like something is not functioning properly, they assured me that this has been a common point of clarification for Toyota hybrid owners for at least a decade and that there is a fail safe emergency braking system that will kick in to prevent a collision caused by a transition on uneven surfaces.
“My bigger concern now is that the third row does not lock in place when stowed. It can fly up, slam back into position, and relock during hard braking. Dangerous design!”
Lemberg Law is currently investigating complaints about the 2021 Toyota Sienna Hybrid brake system to see if owners are protected by lemon law. However, your rights depend on the state in which you live. If you have these brake issues, you might have a lemon. It won’t cost you anything because the law holds Toyota liable for the legal fees arising from lemon law cases. Complete our case evaluation form or call us.
Brian Jones spent more than 30 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.
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2023 Sienna, brakes stop working for a split second. Very scary. Brakes then cone back and work fine.
We have had the “lurch forward while braking” issue on several occasions and reported the problem to the dealership but they were not able to re-create the problem.
I purchased a brand new 2021 Sienna XSE in March of 2021. I noticed this “surge” issue pretty soon into ownership. It appears to happen for me in the first few minutes of driving at the same stop sign leaving my neighborhood. I have only noticed it at low speeds. It is intermittent though. Otherwise I love this van.
From day one with our new 2021 Sienna LE, we’ve experienced the brake surge issue. We live in a flat area with few bumpy roads. Even so, the issue tends to happen once every couple weeks, if not more often. We’ll be gradually braking, when all of us sudden the van lurches forward as if we let off the brake and stepped lightly on the accelerator. I keep a fair bit of distance between me and cars in front, but even so, there have been one or two close calls.
I purchased a certified 2022 Sienna Hybrid in late March 2023. My wife and I are in our 70s and we moved up from an older Prius for the additional space to carry a walker, a 3 wheel scooter, and luggage. We traded off some gas mileage from 47 to 39-40 but the new Prius is too low to enter and exit. We both have experienced the surging discussed in this thread and in fact just experienced a surge as we were parking at a CVS. Not only have we experienced the problem but our son who is a physician noted the problem as he was driving my wife around town. Since so much of this car is operated through electronics, maybe a software or firmware change could be a solution. It is a problem that is magnified by having slower response times to react quickly and safely to prevent accidents.
Same exact brake “surge” issue in both of our 2022 Hybrid Sienna vans. Dealer explains the issue cannot be replicated and the braking system is operating as intended. The issue is concerning and believe this could lead to an accident at some point if not resolved.
I have two issues.
Sienna 2021 had to replace engine at 97,000 due to engine failure would be glad to explain. Was a $6,000 labor only repair. Toyota agreed to supply engine.
Brake slippage from day 1
I am also having same problem for my 2023 Sienna. Its very dangerous to drive on hilly areas where there is more chance of accident due to steep curves and brakes not working for minute second can be deciding factor. Dealer is saying they never heard about this issue and if they are unable to replicate the problem then I have to bear the expenses of service fee which can be 500 dollars or more. How come toyota is not considering this safety concern when this is experiencing by so many people.
Has anyone made any progress with Toyota on this issue? My claim was closed b/c the dealership couldn’t recreate it (of course not).
I am so glad to see this post. It perfectly describes our situation with a 2022 sienna.
I am experiencing the same problem. It is intermittent, but usually seems to be when under moderate braking (not sure I’ve ever braked hard yet) and almost always is when stopping to avoid hitting the car in front of me, which makes this seem absurdly dangerous. Happens a couple times a week. I figure it has to do with the regenerative braking, but since it only happens infrequently maybe it has to do with the state of the battery’s charge or something. It is frustrating that it can’t be repeated easily and that Toyota doesn’t seem to be looking into the problem.
I purchased a certified 2021 Sienna Hybrid in January this year. I had several of these “surge” issue that when the car is traveling probably more than 40 miles and press the brake, there is a moment (less than a second) that you feel the brake is not working and feel the car actually accelerates.
I have the exact same problem with my 2021 Sienna. I just dropped it off at a Toyota dealership. They’re charging me $100 to diagnose it. After reading this article, I feel like the dealership won’t find the problem or they will point to different issue.
I have this exact same problem with my 21 Sienna. My name is Nick and I have been an ASE Certified Master Technician for 24 years. I am well familiar with Automotive Control Systems. I find the gas mileage and mostly problem free hybrid operation of the Sienna to be superior and the gas mileage and power are phenomenal for the size and mass of the vehicle.
I can haul full sheets of plywood at 35+ mpg! I am a red blooded man who rode Harleys and swore to never be in a van! I absolutely love it though and so do my three teenagers!
That being said my wife and I have experienced this exact same thing completely randomly with no rime or reason or consistency. When it happens coming up on a car it’s pretty damn scary. Feels like you blew a brake line briefly, like pedal goes soft and then it lunges forward like you stepped on the accelerator.
Best way to describe it is almost like if you’re ever coming to a stop, and your foot slipped off the brake pedal, and onto the accelerator, and realizing it quickly you return it to the brake again. Hope this helps.
Toyota needs to come up with a fix to make it a more seamless transfer of braking power.
In certain Heavy Equipment, for instance crane winches, there exists a similar power transfer dilemma.
When the winch is in the raise position, the spring apply brakes have to release without the load falling. So the apply back pressure to the hydraulic winch motor to let the motor take over the load seamlessly and brake to release simultaneously.
If Toyota could come up with some kind of intermediary brake or tweak it so it’s a smoother transfer of power somehow, and improve the front seat comfort a little, It would be the perfect grocery getter.
My .02c
Nick
2021 Toyota Hybrid brake system failing as well as continuous problems with parking brake button.
Hi,
I have the same the problem with my 2021 Sienna. The brake stop working and engine light came. Currently at West Coast Toyota and no ETA on parts.