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 problem 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 discussing a “possible acceleration while braking issue” has 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, there is a brief moment when drivers feel as if their brakes have failed. 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 happen.”
Many others comment on the malfunction stating that the transition “should be seamless and instantaneous.”
The general consensus is that if there wasn’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. 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 20 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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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.