2012 Toyota Prius V Brakes Problems

Brake actuator assembly failure on a vehicle with 99,818 miles. Whirring sound when braking followed by lighting of several brake alert lights on dash including PCS and ABS and others. The whirring noise has occured for several weeks, but the light indicators happened on 6/28/26. Toyota has an acknowledged Customer Support Program (20TE07) for this exact failure on this exact and Toyota declined to cover the repair. This vehicle is 14 years old but has well under 150k miles and Toyota will not honor claim though they clearly are aware of the safety hazard.

NHTSA ID

11747171

Incident

Jun 28, 2026

The ABS system has failed. All brake related warning lights have appeared on the dash board and the ABS no longer works. The car will brake for now, but the pedal is mushy. The issue was diagnosed by a dealer. The diagnosis from the dealer, based on diagnostic trouble codes they did not provide, is that brake fluid is leaking in the master cylinder and brake booster. The recommendation is to have both the master cylinder and booster replaced. This vehicle has 143,000 miles on it. No accidents have occurred as a result of the brakes yet but how long before the brakes ultimately fail is unknown.

NHTSA ID

11745426

Incident

Jun 2, 2026

ABS, brake, and traction control lights, all illuminated at once on the dashboard. Inspection found DTC C1391 indicating the accumulator is leaking or failing to hold pressure correctly. We are advised that the braking system performance will decline, eventually failing. An very expensive repair is required and Toyota apparently has a shortage of the parts required. We cannot drive the vehicle given the potential of braking failure and cannot get it repaired in a timely manner for lack of Toyota parts.

NHTSA ID

11743546

Incident

May 29, 2026

The contact owns a 2012 Toyota Prius V. The contact stated that while driving at an undisclosed speed, the brake master cylinder was constantly cycling. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic to be diagnosed or repaired. Most recently, while the vehicle was turned off, the brake master cylinder was cycling. The contact stated that while the keys were in his hands and standing several feet away from the vehicle, the brakes started cycling. The manufacturer was notified of the failure but offered no assistance. The approximate failure mileage was 140,000.

NHTSA ID

11715101

Incident

Feb 2, 2025

Mileage

140,000 mi

The power assist braking system failed while I was driving in the rain. I was approaching a stoplight and I had to push down a lot harder and farther than I typically have to in order to stop. Luckily I was not going that fast and there were no cars ahead of me, but I stopped beyond where I had intended at a busy intersection. No warning lamps or messages had been illuminated prior to this happening. After the failure, the Brake system, ABS, and SLIP indicator lights were on and remained on when the car was restarted. An independent service center used a scan tool and found code C1391 stored in memory, indicating that the brake booster is unable to hold pressure due to an internal leak. The vehicle has not yet been inspected by the manufacturer, police or insurance, but can be available upon request.

NHTSA ID

11704509

Incident

Nov 26, 2025

I bought this car over a week ago for a good price, performed fine until I’m driving it home on the interstate and some abs/brake lights came on the dash. I enter my city and notice the brakes aren’t performing as tight as they were during the test drive. A few days later I take it to a local dealership to get it looked at. The brake actuator and pump had gone bad, causing this issue. It cost almost $5,000 to fix there, I couldn’t afford it so I had to only pay the $185 for the diagnostic. It’s an on and off thing, sometimes the lights go away and it brakes as it should, but most of the time the lights are on and the brakes don’t work as they should. I fear one day the brakes may eventually give out on me and cause an accident. I am available for inspection.

NHTSA ID

11703955

Incident

Nov 26, 2025

After 13 years and 112,000 the brake booster and brake booster pump went out on my car. Toyota extended the warranty to 10 years because of this issue. Now just outside of the 10 yr mark my car has this issue and Toyota will not cover it. This is a huge expense and also a major issue with this year and model of car.

NHTSA ID

11692218

Incident

Aug 30, 2025

I have a Prius v 2012, and the lights for abs turned on and when I checked on internet Toyota was repairing the part for 150k miles and 10 years but this is a safety feature my car is now at 149922, And while I was on road suddenly the signs came up and I the brakes were hard, and this is a problem for my safety and for others too since It doesn’t brake well

NHTSA ID

11686967

Incident

Sep 2, 2025

While driving on the interstate I went to slow down to merge and my brakes failed. The following warning lights came on: Master Warning Light (yellow), Brake System Warning Light, Brake System warning light (red), ABS Warning Light, and the Slip Indicator light. My vehicle was towed to a Toyota Dealership and after running a diagnostic test, they confirmed that it was the "Break booster with accumulator c1391 stored internal leak of accumulator and need immediate attention" which they quoted at $4,295.68 to fix. After researching the issue saw A Customer Support Program 20TE07 was issued taking responsibility for the faulty Brake Booster Pump Assembly however only covered the repair for a two-year period and only if it was one of the identified diagnostic trouble codes listed in the CSP issued by Toyota but expired in Feb 2022. The code pulled from my vehicle 3 days ago was listed in this document, but the coverage only covers until Feb 2022. This is not a normal wear and tear issue, it is a faulty part that Toyota identified as a life and death safety concern but refuses to do anything about because mine didn't show an issue within their 2-year CSP timeframe. Toyota identified that there are roughly 118,950 2012-2014 model year prius V with a production period of late September 2010 to mid-November 2014 vehicles that this faulty part affects along with everyone else on the road with these vehicles as it causes failure of the brake booster pump assembly, which leads to a loss of braking assist and the deactivation of the Vehicle Stability Control system. For the safety and lives of the owners of these vehicles and all of the other lives of the drivers on the road that this could affect in the case of this faulty part should there be a catastrophic accident, like mine could have been, a nationwide recall on this part MUST be issued.

NHTSA ID

11668719

Incident

Jun 21, 2025

The contact owns a 2012 Toyota Prius V. The contact stated that while driving at an undisclosed speed, the service brakes warning light illuminated. The vehicle was taken to the dealer, who diagnosed failures with the brake booster assembly and brake booster pump assembly. The vehicle was not repaired. After investigating the failure, the contact related the failure to Customer Satisfaction Program: 21TE01. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was unknown.

NHTSA ID

11660422

Incident

May 12, 2025

My wife was driving home and four dashboard error lights illuminated (Brakes, ABS, SLIP and a yellow light_) The brakes suddenly "went soft" (in her words), and it freaked her out. I now learn that I need to have the brake master cylinder and a booster pump assembly replaced at a cost of over $4,000. Ouch!

NHTSA ID

11643279

Incident

Jan 29, 2025

While driving suddenly the ABS and vehicle traction lights came on and the car became very slippery, was unable to stop without an excessive amount of space between the car in front of me and me. While looking at the car, I realized the actuator brake booster pump. I then found multiple websites and forums dedicated to people with the same problem ( brakes suddenly not functioning correctly while driving) with the same model car as I have, and there was a service bulletin that shows Toyota acknowledged there was a problem ( and a fix) but with the date of the bulletin and the date it was to be fixed within, it was near impossible to actually have it fixed. My car has 87,000 miles and the brake system is dangerous

NHTSA ID

11639525

Incident

Jan 25, 2025

Brake booster pump assembly. Toyota has sent a notice of extended warranty for this vehicle which has expired. Without repair, the brakes will loose compression and stop working.

NHTSA ID

11637372

Incident

Jan 14, 2025

The issue is my brakes failed on me all of a sudden. My abs light, traction control light, and brake light came on out of nowhere. Suddenly didn't have brake pressure. Had to pump the brakes a few times before the car would stop. Luckily I didn't hit anything or anyone. I brought the car to Prius specialist and they diagnosed it saying it was the ABS Actuator Pump Assembly and Master Cylinder. They said it is quite common in the 3rd generation of Prius'. I contacted Toyota North America and they said they had a recall on the parts but it ended Dec 31st, 2021. I bought the car in 2022 unknowingly. Was quoted around $4000 to repair it parts and labor. This is a safety issue that should not be limited to time. Luckily I was not on a Freeway or anywhere where I could have done damage. This issue is a hazard to myself and other people on the road. Toyota needs to resolve this.

NHTSA ID

11636624

Incident

May 4, 2024

Anti lock brake malfunction. Code c1391 leak in brake accumulator. This seems to be a common code for brake issues with Prius. The cost to repair is significant, more than the value of the car. This is a certain safety issue that needs to be addressed. This is clearly a Hazzard and will cost lives to those who cannot afford the cost of repair.

NHTSA ID

11636405

Incident

Jan 16, 2025

I write to add my voice to the litany of complaints in support of NHTSA investigation DP23005. While on an road trip recently the ABS, Traction Control, and Brake warning lights all came on. The brake felt squishy and didn't seem to be functioning as confidently as before. I altered my driving (giving plenty of distance, lowering my speed) so that in the event the brakes quit working I would have an exit strategy. I took it to my Independent Service Center as soon as possible who found the code C1391 and diagnosed the need to replace the master cylinder / booster assembly for several thousand dollars. Of course I must do this in order to remain safe but this is clearly a safety issue that could have been catastrophic. Meanwhile I am out of a car for several weeks until the part arrives and out of at least $2000 as quoted by my mechanic ($1640 for the part). The car only has 146,500 miles on it so otherwise would have plenty of life left in it. I'm filing this complaint to add my voice to the open petition and toward the NHTSA's investigation in strong support of holding Toyota responsible for PREVENTING injury and death through a proper recall, as well as against burdening the car owner with the costs of making up for Toyota's negligence on this issue. At the least they need to cover the cost of these necessary safety repairs when they are warned by the lights and reinstate their warranty extension for this issue

NHTSA ID

11621521

Incident

Oct 23, 2024

I write to add my voice to the litany of complaints in support of NHTSA investigation DP23005. While on an interstate road trip recently the ABS, Traction Control, and Brake warning lights all came on. The brake felt squishy and didn't seem to be functioning as confidently as before. I altered my driving (giving plenty of distance, lowering my speed) so that in the event the brakes quit working I would have an exit strategy. I took it to my Independent Service Center as soon as possible who found the code C1391 and diagnosed the need to replace the master cylinder / booster assembly for several thousand dollars. Of course I must do this in order to remain safe but this is clearly a safety issue that could have been catastrophic. Meanwhile I am out of a car for several weeks until the part arrives and out of at least $2000 as quoted by my mechanic ($1640 for the part). The car only has 146,500 miles on it so otherwise would have plenty of life left in it. I'm filing this complaint to add my voice to the open petition and toward the NHTSA's investigation in strong support of holding Toyota responsible for PREVENTING injury and death through a proper recall, as well as against burdening the car owner with the costs of making up for Toyota's negligence on this issue. At the least they need to cover the cost of these necessary safety repairs when they are warned by the lights and reinstate their warranty extension for this issue ("POL18-03") which expired for my vehicle in August of 2021.

NHTSA ID

11616998

Incident

Sep 21, 2024

have suddenly brake failture, w code c1391, it problem persist car do not stop by pressing brake , it is too dangerous to drive this car!!!! what you can help me w this recall or rebate option for brake repair?

NHTSA ID

11614556

Incident

Aug 30, 2024

The Toyota Prius of this generation has a known defect in the brake booster pump assembly. About 2 weeks ago the dash lights came on for ABS, Traction control, general warning light. The brakes work but feel soft, and a motor sound pulses behind the steering column every 8-10 seconds. My mechanic pointed out it is a known problem where the ABS booster pump has a faulty valve that doesn’t allow proper pressure to build to engage ABS system. I cannot afford the Repair: $3890 for master cylinder and brake booster. My concern is that most people can’t afford this repair and without a functioning ABS system, people are put at risk from this generation of Prius. Toyota did offer a customer service program acknowledging the issue, but that program only helped if these issues occurred before 2022. With the known issue, why wasn’t a recall required? Toyota should be required to address this safety issue. How many of these Prius are on the road where customers are expected to perform a $4,000. Repair to keep up the safety standards. The car is available for inspection upon request. Thank you.

NHTSA ID

11614025

Incident

Sep 1, 2024

About three weeks ago, my daughter told me that several lights were on on her display. I checked and among them were the traction control and 2 other related to the brake system. I looked up possible causes on the Internet and it seemed the brake booster/master cylinder could be a culprit, but then I checked the fluid reservoir and the fluid was low, so I topped it off, drove the car, pumped the brakes a few times and all the lights went off. About a week later the lights were back on. I checked all the lines and saw not visible signs of leaks and decided to take it to a mechanic. I took it to a local mechanic and I was told that the brake master cylinder with brake booster failed and had to be replaced. Afterward the brakes were repaired I went to 2 local Toyota dealerships to check the price of the parts. The first dealership provided the prices without any discussion. At the second dealership, the employee who waited on me, after I provided her the VIN and told her that I need the price of the brake booster/master cylinder,m told me that there was a service notice on the booster/master cylinder because of a high rate of failure and that I would have to check with the service department before she could sell me the part. This is concerning, if Toyota knew/knows that the part has a high rate of failure, why wasn't a recall notice issued?

NHTSA ID

11610479

Incident

Aug 1, 2024

I was driving and all of a sudden the emergency brake light, the ABS brake light and a couple more turned on and I had no more brakes. I had just driven 25 miles with it and stopped at many red lights along the way with no issue and NO WARNING lights. I could have gotten into a major accident if it had happened anywhere else in my route. Fortunately, I was about a mile from my house and the hybrid motor helped slow the car down. I was unable to stop at any stop sign in my development and here again was very fortunate that there were no cars along the way. Once I got home, I got it towed to Toyota and was told it is an internal failure of the actuator. I contacted Toyota America and was just told that there was a campaign to repair this but that I had passed the date. My car has only been serviced at the same Toyota in my city since I got it. I religiously brought it every 5000 miles. I am shocked that they never mentioned this campaign to me and that they didn't initiate a repair during the campaign. This is a major issue that needs to be addressed and Toyota needs to be held accountable.

NHTSA ID

11610467

Incident

Aug 21, 2024

Brake master cylinder and brake booster accumulator assemblies brake parts from this vehicle failed on another vehicle.

NHTSA ID

11608645

Incident

Aug 15, 2024

After starting the car on 7/30/24, the Brake System Warning Light, ABS,Slip Indicator, and Master Warning Light all came on indicating an issue with the brake system. We were able to get it to the local dealership and when they ran diagnostics on it, it returned a code C1391, which confirmed the issue. This was addressed in 2020 by Toyota, but only for cars 10 years or 150,000 miles old. Our car is a 2022 with 105,000 miles on it, but we are outside of the year limit (car was 8 years old when the Customer Service Program was released).

NHTSA ID

11605920

Incident

Jul 30, 2024

The brake booster noise, brake problem, brake booster pump internal mail function

NHTSA ID

11603781

Incident

Nov 8, 2023

2012 Toyota Prius brake actuator failure . While driving my Toyota Prius the braking system failed, this was on a large road and so posed a major danger to not only me, but the passengers in the vehicle and the vehicles around us. Thankfully nobody was hurt. After having the vehicle inspected by a Toyota dealership the problem was found to be the “Actuator/accumulator” and after speaking with the dealership it has come to be my understanding that this is a common and unavoidable problem with Toyota Prius models. There were no lights or warnings on in the vehicle until after the brakes gave out. I cannot understand why this has not been recalled when it is a manufacturing issue on Toyotas end that poses a significant danger on the roads, and am wondering what the reimbursement policy for this is as it came out to be quite expensive.

NHTSA ID

11599562

Incident

Jun 22, 2024