2011 Toyota Prius: brake failure

Filed Dec 9, 2025 · Brakes · CA

The Master Cylinder started failing while I was driving the car, the car only has 138k miles, the dashboard lit up like a Christmas tree, all the warning lights were on, and when I went to step on the brake, I had to push it all the way to the floor for any braking to happen. I remember being scared for my life because I had almost no brakes which I could've got into a serious accident or been killed had it failed completely. I took the car to the dealer and they diagnosed it with code C139: Abnormal Leak at Accumulator Assembly, and recommended a new Brake Booster with Master Cylinder Assembly and Brake Booster Pump Assembly with Bracket. The car by age was not in Toyota's extended warranty on the parts but mileage-wise it still is, so I was footed with a $4-5k bill to replace both parts.

Filed Jan 31, 2025 · Brakes · CA

While driving on the interstate, the "brake", "TCS", and "ABS" lamps lit up. The brake pedal was stiff and couldn't be depressed. The vehicle initially did not decelerate while attempting to push down on the brake pedal. While maneuvering off the interstate on to the exit lane, the pedal remained stiff however, the vehicle did begin to decelerate. Critically, the amount of time needed to bring the vehicle to a stop was significantly longer than normal. This brake failure could have resulted in a catastrophic, life threatening and/or deadly accident. The DTC associated with this brake booster and pump failure is C1391 which is referenced in TSB-0024-19. This is a known problem that exists in Priuses manufactured between 2010-2015 and addressed by Toyota with CSP(s). The CSP takes a reactive approach to this serious safety concern as owners who "have not experienced the condition described" were informed that "there is no action necessary at this time". The extended warranty of 10 years or 150,000 miles is not applicable to countless drivers who are experiencing this failure caused by "internal malfunctions" outside of this arbitrary time/mileage frame. A letter was sent to the federal safety agency on 9/19/19 by the president of Claremont and Capistrano Toyota to petition for the initiation of a Defect Investigation regarding this issue. The letter notes that this brake defect is "causing crashes that are injuring people- and Toyota is mishandling it". The advisor assigned to this repair estimated that they see this issue 1-2 times a month and increasingly, drivers are not covered by the CSP. Toyota is failing to take a proactive approach to this dangerous safety issue by telling owners to essentially wait and see if they experience this failure and then failing to take responsibility for said costly failure should it occur outside of their arbitrary time/mileage frame. This approach to safety is egregious, irresponsible, and unethical and it is putting countless lives at risk.

Filed Jan 27, 2025 · Brakes, Electrical · CA

In 11/2024, I started experiencing intermittent noises coming from the engine compartment of my 2011 Toyota Prius. The initial sound resembled the buzzing noise generated when first starting the vehicle. Then the noise started to persist for extended periods after the vehicle was turned off. It would oscillate between buzzing for approximately 10 seconds & remaining dormant for about 1 minute, repeating this cycle. The duration of these cycles could extend for up to 20 minutes. Concurrently, I experienced several instances where the brake pedal would abruptly become stiff & difficult to press. Notably, no warning lights were illuminated on the dashboard. Recognizing these symptoms as unusual, I conducted online research and discovered that the issue could potentially stem from a malfunction in the “brake booster pump and assembly.” Given the potential for a loss of braking power and the risk of personal/public safety, I scheduled a diagnostic inspection at Toyota of Poway, Poway, CA, on 12/18/2024. It confirmed the presence of a problem with the brake booster pump and associated components. In light of this diagnosis, I made the decision to refrain from driving the vehicle until the repairs were completed. The repair costs amounted to $3,475.47. I found I had received a notification from Toyota’s Customer Support Program, designated as “Customer Support Program Notification-ZJB.” This notification explicitly acknowledged this defect & provided a repair coverage policy that stipulated a coverage policy of which I’m no longer entitled to. Despite not meeting the eligibility criteria for the repair coverage program, I am deeply troubled by the fact that this recognized defect persists in vehicles currently on the road, such as mine, without any corresponding recall action and subsequent repair costs covered by Toyota. Fortunately, I was spared from any accidents as a direct consequence of this issue. Many similar complaints here support this dangerous issue!

Filed Aug 6, 2024 · Brakes · VT

On April 28, 2024 I was driving when my brakes became squishy and my ABS warning light, red brakes warning light, and traction control light came on. I was very fortunate to be close to my destination and only traveling under 25mph. Roughly a week later it was driven approximately 150ft (on private property) and the brakes were very unresponsive. The car was never accelerated past 3mph for that move. The loss of braking was sudden and happened without any prior warnings. Had I been on a high traffic, high speed road, I believe it likely that this would have resulted in a catastrophic accident. The Master Cylinder Actuator Assembly and Brake Booster Pump Assembly failed. This was confirmed with OBD and a Snap-On Solus Ultra scanner. Both parts have been removed and are available for inspection upon request. They have not been inspected by anyone. I did contact Toyota about the braking issue and they did not express any interest in the issue or inspecting the failed parts. To make my Prius road safe and legal, I needed to replace the Master Cylinder Actuator Assembly and Brake Booster Pump Assembly. These parts were bought from Toyota, who has so far profited from my car's brake failure.

Filed Mar 8, 2024 · Brakes · OH

I bought this car new in 2011, and it is now driven by my daughter. The brakes started having problems around 2019, and the car was taken to Toyota service. It was thought to be a tire issue and the tires were replaced, but the brake issue remained. In February 2024, all the dashboard brake lights came on, and my daughter immediately took the car to Toyota service. The problem was a defective and leaking brake booster pump assembly, a defect well known to Toyota, and the subject of extended warranty on this model (10 years or 150,000 miles) and a recall by Toyota on some other models. Since it was after the 10 year period (despite reported problems during the 10 year period), corporate Toyota told the Toyota dealer service department and our family that they would not cover the $3500 repair bill incurred. This should have been a recall. I am horrified to think what could have happened to my daughter with defective brakes. Corporate Toyota is well aware of this defect. Even a Toyota dealer has previously reported it to the federal safety agency. [XXX] . I request corporate Toyota pay for this repair and issue a recall for other unsuspecting drivers of these vehicles. This is a potentially lethal defect that needs a recall, not a post brake failure repair. I send my great thanks to you for investigating this. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 21, 2024 · Brakes, Driver assistance · TX

The 2011 Prius has an issue known to Toyota, in which the brake booster pump fails after an indiscriminate amount of time, leading to significant loss in braking ability and control. Toyota knows of this because they issues an extended warranty coverage for these vehicles and this issue, that did not extend beyond 10 years, or 150,000 miles, whichever comes first. [XXX] ) When I was driving my car down Highway [XXX] I lost braking control completely, with a series of constant beeping starting to emit from the braking system. Luckily through mashing the brake pedal and using ebrake I was able to get the car to slow down and pull off the highway. The brakes sporadically and randomly cut in and out with the power braking, leading to uncontrolled stopping power and jerky or inactive braking. There had been lights on the dash indicating the traction system or braking system had issues but these would frequently turn off and on and didn't result in a loss of braking ability or performance and had been there a couple months. Upon taking the vehicle to a Toyota Dealership (Charles Maund North Austin) I was told it was a C1391 error regarding a failure of the brake booster pump assembly and that it would need to be replaced and reprogrammed for about 3300 dollars. After looking online I saw there were many other people with this issue, all who were unable to fix this in the given 10 year frame. Many unsuspecting second owners of this vehicle do not know that there is a hidden danger waiting for them when their power brake pump assembly fails. If I had been a less experienced driver I would've certainly crashed and Toyota, knowing of this safety concern already, should have done the right thing and issue a recall for these vehicles. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 17, 2023 · Brakes · FL

Dear Mr; I own a 2011 Toyota Prius, and this week my brakes failed while driving down the highway. The ABS and Break lights and the ESP warning light on the instrument panel come on. The brake pedal is hard and has an intermittent hum in the engine area. The scanner gave the code C1391 / ACC PRESS abnormal leak error. I want to file a formal claim against Toyota for the failure of my car's brake system and request repair/replacement of my car's brake system. --------------------------------------------------------------------------------------------------------------------------------------------- What component or system failed or malfunctioned, and is it available for inspection upon request? BRAK SISTEMS / YES, IS AVAILABLE FOR INSPECTION. How was your safety or the safety of others put at risk? IT WAS DIFFICULT TO BRAKE / THE CAR WAS DEVIATED WHEN APPLYING THE BRAKE / I LEFT THE ROAD DUE TO THE RISK OF A COLLISION BY NOT HAVING THE ACTIVE BRAKING SYSTEM. Has the problem been reproduced or confirmed by a dealer or independent service center? YES / INDEPENDENT SERVICE. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? NO. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? NO

Filed Dec 5, 2022 · Brakes · NY

ABS warning light came on, followed soon by a beeping warning sound. Brakes felt odd. A few minutes later, complete loss of brakes.

Filed Sep 20, 2022 · Brakes · 155,000 miles · VA

The contact owns a 2011 Toyota Prius. The contact stated that while driving at various speeds, the brakes failed to operate as needed upon depression with several unknown warning lights illuminated. The contact took the vehicle to an independent mechanic where the vehicle was diagnosed with a defective brake control dynamic system. The contact was referred to the dealer where they confirmed the failure and provided her with an estimate for the repair. The manufacturer had yet to be notified about the failure. The vehicle had yet to be repaired. The failure mileage was approximately 155,000.

Filed Aug 8, 2022 · Brakes · FL

My brake accumulator pump has begun running much more frequently than it should. Upon extensive online searching, I learned that this condition is warning sign of an eventual failure of the brake booster pump and/or master cylinder which will cause brake failure at an unpredictable time when the brakes are applied. I understand that this condition is known by Toyota and has been addressed by "warranty enhancement ZJB". However, my car is outside of the cutoff age/mileage. The president of Capistrano Toyota in Southern California made this problem known to you with an urgent letter dated 9/19/19 and expressed why this NEEDS to be a recall issue, not just what it is now. The reason is because not only has Toyota time limited repair coverage, they would not do the repair until failure occurred....a totally illogical and dangerous plan. I should not have to pay ~$3000 to have this well-known problem repaired at my own expense just because the invitable failure hasn't happened yet, and I'm not within Toyota's arbitrary time limits for having the repair covered at no cost. The symptoms I am experiencing are precisely those that are the precursor to this known failure. Why has the federal safety agency not acted to force this issue to be a full recall? You are putting lives at risk by not acting in a timely fashion given the Toyota dealer's warning I mentioned above.

Filed Apr 6, 2022 · Brakes · FL

The brake actuator failed leaving the vehicle with no brakes.

Filed Feb 8, 2020 · Brakes · 128,000 miles · CA

I have been lucky to miss closed-call hitting the car in front of me after skidding. When I apply brakes going down the ramp, the car skids and the brake doesn't stop the car until I get pretty close to the car in front of me. I am more concerned because some parts of the road are uneven where I live that increases the chance of brake failure. It happens on surface roads when there is a bump too. The braking distance increase when the street is wet.