The contact owns a 2010 Toyota Prius. The contact stated while driving at various speeds, the brake pedal would depress to the floorboard initially without warning. Over time, the brake pedal had become stiff upon depression with several warning lights illuminated on the instrument panel. The vehicle was taken to an independent mechanic where a code reader confirmed a defect with the braking system. The vehicle was then taken to another independent mechanic where the vehicle was diagnosed with a defective brake booster. The mechanic then informed the contact of NHTSA Campaign Number: 13V235000 (Service Brakes) which was linked to the failure. The dealer was notified of the failure and informed the contact that the vehicle was not included in the recall. The manufacturer was notified of the failure but offered no assistance. The vehicle was not repaired. The failure mileage was approximately 153,000.

- Independence, MO, USA

Prius Gen III has a known defect with failing Brake booster parts. In Nov 2023, while driving my 2010 Prius (~160K miles), suddenly brake, ABS, Traction control, skid indicator lights popped up on the dashboard and I have lost the ability to brake effectively. There was a brake pressure loss and I had to slam hard the brakes to slow the car. The error code was 'C1391' and the mechanic diagnosed it as failure of Brake booster parts ABS Brake booster pump (accumulator) - part#47070 47060 and Brake master cylinder (actuator), part#47050-47140 and he replaced both these parts. Toyota is aware of these failures which are very frequent and hence they issued a brake booster -??customer service program-?? ZJB - which extended the warranty for these parts. But many of us were not covered by this warranty either because of the time or mileage restrictions. This was a costly repair and we had to fix it out of pocket at the cost of ~$3000 as this is safety hazard without proper braking. To make matters worse, 3 months after the repair, the newly installed parts failed again and I had to go through the same repair. I called to Toyota to complain about this and they cannot do anything about it and advised me to report it to NHTSA.

- San Jose, CA, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving at 55 MPH, with the brake pedal was depressed and went to the floorboard. The contact stated that the brakes failed to adequately slow the vehicle. The ABS warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the brake booster. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 13V235000 (Service Brakes) however, the VIN was not included. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 120,000.

- Chicago, IL, USA

My car accelerated significantly on its own while I was pulling into a parking stall in a private parking lot. It caused my vehicle to jump a curb and accelerate up a dirt divider and push over a bush that was planted in the dirt divider. Depressing my brakes did not Decelerate the car, so I pressed the Park button to eventually stop the vehicle. I-??m not sure what speed it was traveling when it accelerated, but I could smell burning rubber at the end of the incident. I-??m not sure when the smell first occurred.

- Irvine, CA, USA

Brake booster assembly failure. Code C1391 - accumulator pressure leak. Toyota previously agreed to extend the warranty on this part on this year of Toyota Prius due to the known issue and the time limit for this repair was set to be in 2019. Toyota agreed to replace the unit only if it fails before that timeframe. My Toyota got recently affected by this issue resulting in over $3,000 estimate for a repair as Toyota no longer covers this repair for my vehicle. That-??s a known issue with this part, Toyota knows it-??s faulty and yet no recall has been issued. Now I have to pay for a repair out of pocket. I can-??t drive the vehicle until it-??s fixed. This should be handled as a recall with all faulty units being replaced regardless of millage. A few people opened lawsuits on this issue before and some got a settlement. I believe there is enough evidence that this should be classified as a recall and a free of charge repair should be provided to the owners. The brake booster unit has been buzzing a lot for quite a few months ( due to the pressure leak it had to work more than normal). Now it completely failed with the leak being so excessive that the brakes are very soft.

- Grandville, MI, USA

I-??m encountering multiple dash lights with the brakes being very unreliable and no that-??s no regenerative breaking. I checked with an obd2 kit and the app shows that I have a code C1391.

- Long Beach, CA, USA

Faulty brake boosters that crack and leak, making brakes unusable and draining the battery (diagnostic code C1391). There was a Toyota service repair where they exchanged the faulty brake boosters with properly working ones, but it has lapsed.

- Nashville, TN, USA

[XXX] We took in 2010 Prius to Toyota Dealership in Pharr Texas because road hazard light, ABS, Brake and low tire alarm came on while driving car. They ran diagnostic and found out that the brake pump assembly and brake cylinder assembly has to be replaced. We called Toyota Cooperate to ask for assistance to pay for cost and after 4 weeks of reviewing issue they said they could not help us because the CSP had expired. This car was given to us by a friend of ours and they had not used it for 2-3 years so we got it we repaired and got car running again. After we drove it we came across this problem with the brakes. This car was was built in the same plant as the other recalled cars going by by the vehicle number. We believe that the CSP should be extended or changed to a Recall" Will you help us or direct us to whom we can contact with this safety issue" I have the Toyota diagnostic report from Toyota and Toyota Corporate Letter on email. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Mcallen, TX, USA

My 2010 Toyota Prius hatchback suddenly had 4 or 5 warning lights appear on the dashboard and my brakes failed to function properly. It felt like the power brakes was turned off ! Although I did get the vehicle stopped, it surely was a dangerous situation. I understand that Toyota knows about this problem, and have read that it was warranted if this happened before 150,000 miles. My Prius has approx 167,000 miles right now and to replace the Brake Actuator, the cost will be $ 3 - 5 thousand dollars-??absurd amount in my opinion. Since this critical feature (brakes) has a long known history of being faulty on Toyota vehicles it should be warranted for at least 25 years and at least 300k ! My Prius is -??unsafe to drive-?? and is nothing more than a paperweight-??I repeat, Toyota knows, and has known about this defective brake actuator problem for years and years!!! Please lean on Toyota to up the warranty of this faulty brake problem for the MANY, MANY Toyota owners who have purchased the Toyota product and and NOT screwing the public like they are doing now !

- Indianapolis, IN, USA

A warranty extension went out a few years back that said one might receive a "CHECK PCS SYSTEM" warning on the dash. This has happened to us, along with 7 other lights on the dash. Between the brakes being much less responsive, and all of the pre-crash warning / adaptive cruise / radar features being disabled, this could have caused an accident. The dealer checked out the car and states that the brake actuator has a leak and that it will be a costly repair - no less than $3000. This suspiciously all happened *just* outside of the warranty window (we are within the allowed number of miles but just out of time), and also suspiciously after Toyota released an upgraded version of the actuator, and *also* after a bunch of people are experiencing the same failure. Our best assessment at this time is that the brake actuators have a factory defect and that a recall should be done.

- Altoona, FL, USA

The brake accumulator has failed on my prius which then deactivates regenerative braking, traction control, abs, and stability control. The lights for traction control, ABS, and stability control and parking brake are shown on the dash. The result for the driver is that the brake pedal has the same pressure, but does nothing until about 25% of pedal travel. At this point, the mechanical brakes will engage and provide a very sudden and jerky application to the brakes. In other words, a very non-linear brake control is present and is incredibly difficult to predict. If this vehicle is operated on the motorway, the safety of the vehicle's occupants as well as others on the road is greatly reduced. Street Toyota has confirmed this issue and its effects. They want to charge $3600 to fix this issue even though the car is only worth $5k. This problem has been investigated in the past buy Toyota and the NHTSA. Toyota has applied an extended warranty for this part meaning that they will only replace it once it goes out. They also failed to notify their consumers about this matter. It is a serious issue that has put many lives at risk and has caused multiple injuries. It is a matter that should not be ignored by either the NHTSA or Toyota.

- Canyon, TX, USA

I noticed that the ratcheting parking brake pedal has stopped ratcheting correctly, and I planned to have it inspected on the next scheduled maintenance. Recently, the brake system illuminated the traction control, ALB and "BRAKE" lights simultaneously, and the braking power diminished by more than half, with no braking until the pedal was halfway down. I depressed the parking brake pedal a few times, which cleared the "BRAKE" symbol and the problem stopped and normal braking returned. This has now happened three times with the same fix. It appears that when the "BRAKE" symbol is no longer illuminated, the problem goes away. This appears to be a software problem that triggers a braking problem to engage the traction control and ABS icons when the "BRAKE" icon associated with the parking brake is illuminated. This web site has other instances reported with the same symptoms, and Toyota had a service bulletin, which has expired, which leads to a $2000-$3000 repair bill to replace a brake booster. It appears to be software related to me, not mechanical. It poses a safety risk because braking performance is severely compromised with no warning. NHTSB needs to look into this, as rear end accidents can easily happen if strong braking in heavy traffic is required to avoid a collision. I recommend that a recall be established to fix this. An alternative cause may be a misaligned micro switch in the parking brake mechanism, which has been experiencing problems. This could lead to the "BRAKE" light being illuminated, and sending a bad signal to the computer.

- Upper Arlington, OH, USA

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- Ranson, WV, USA

I was in my 2010 Toyota Prius with my two children when I suddenly lost my brakes, with luck I was able to let off my gas and coast to a stop. Now I am left with a 3,000 dollar repair. I now know what the price of my children and my life is worth to Toyota! To find that this has already been a problem with no notification is ludicrous!

- Reedville, VA, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving 50-55 MPH, the ABS, traction control, and brake warning lights illuminated. The contact called the local dealer, but the vehicle was not diagnosed or repaired. The vehicle was taken to an independent mechanic and the contact was informed that the brake booster assembly needed to be replaced. The manufacturer was contacted, but no assistance was provided. The approximate failure mileage was 139,999.

- Hicksville, NY, USA

All the lights on my dash board came on suddenly, and the brake emergency, traction control and ABS lights stayed illuminated. Upon exiting the interstate I could not come to a complete stop at the end of the exit, which was very scary. Fortunately the cars driving on the road the exit merges into did, so we avoided a terrible accident. The brakes were spongy and not operating properly after that. The next day with all the lights still on, I slowly drove (20 mph) to the local Toyota Dealer, who claimed that error code (C1391) was being displayed and according to Toyota, that means the Booster is or will be leaking. Therefore the Pump and Booster needs to be replaced (estimated at $3K). No lights or errors were given before the incident, the brakes just suddenly malfunctioned. However Toyota apparently is aware that the booster and pumps fail without warning, because I discovered with an on-line search that code had a "customer extension" warranty (by googling the code C1391), I called customer service but they refuse to help. They claimed I was mailed a letter in October 2018 (they didn't offer to supply a copy.) However, I never received a letter or any notice from Toyota or the Toyota dealer that I have repeatedly used since I bought the car in 2010 (I have had brakes replaced there when it was under 150k and no one said anything!) Now they are stating that the extension has expired as it was only good up to 150,000 miles or 10 years which ever came first. I can't understand why they have a known brake issue and not replace the part when the vehicle is already at the dealer (It's there for every oil change 3 x a year!) Brakes are an important part of a vehicle, a failure like this should have been recalled, and Toyota should have been made to replace the faulty parts!

- Newport, KY, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving at an undisclosed speed, the contact depressed the brake pedal and noticed an abnormal humming sound. The contact stated that the failure had been intermittent since 2016. The contact stated that the failure had become persistent. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure but did not assist. The failure mileage was approximately 296,842. The VIN was unavailable.

- Ranson, WV, USA

Recently, I had ABS failure in my vehicle and warning lights came up on my dash with code C1391 which indicates a problem with brake booster assembly and pump. Now I am afraid to drive it because the brakes seem that they could fail at any time and I cannot break quickly when needed. Toyota is aware there is a problem with the brake booster assembly and pump based on prior Customer Support Programs (my vehicle was not included since warning lights were not present at the time), class action lawsuits, and petitions to NHTS about this issue. I believe the problem is prevalent enough and brakes are significant for driver safety that there should be a safety recall. My vehicle has less than 150,000 miles. I called Toyota to complain about the problem as I know it is very common among Prius owners, but they have said there is nothing they can do.

- Kapaa, HI, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving at an undisclosed speed, the ABS and brake warning lights remained illuminated, and the brake pedal was firm while depressed. The contact stated that the vehicle failed to immediately stop while depressing the brake pedal, causing the stopping distance to be extended. The cause of the failure was not yet determined. The manufacturer and local dealer were not notified of the failure. The failure mileage was 120,000.

- La Palma, CA, USA

While operating the vehicle at normal highway speeds, the car suddenly had the ABS, Traction Control, and Brake lights all come on. The vehicle did not operate or sound any differently at the moment all the lights came on. However, over the next week there developed a mild humming coming from somewhere in the engine bay approximately behind the dashboard. My mechanic identified the problem as the brake booster and pump assembly failing and informed me that the vehicle may drive normally for sometime but the brakes will fail suddenly once the brake booster and pump fully fail. Thus, making operating the vehicle extremely dangerous. I am currently waiting for a Toyota specialty mechanic to become available to replace the brake booster and pump assembly at a cost of +$3,000. Please investigate this issue, there are many people experiencing this issue with the 2010 Prius models.

- Ben Lomond, CA, USA