2014 Toyota Prius: brake failure

Filed Oct 16, 2026 · Brakes · TX

My vehicle is experiencing the well-known brake booster failure. This started at 90,000 miles, with an increased frequency in the running of the brake booster. It has steadily gotten worse, and now the pump runs with every brake application or every 13 seconds. There is now a hissing sound when I apply the brakes. I have repeatedly taken this to Toyota dealers and have been told: "The system is working as designed; no issues found". When I asked why the pump runs so frequently. No response. This is a $4,000 repair that Toyota should step up and fix. The next step in the degradation of this part is a loss of brake pressure. I tried resolving this matter with Toyota Corporate and was denied, even though my mileage is well below the extended coverage for this part of 150K miles and 10 years.

Filed Sep 4, 2026 · Brakes · TX

While driving my 2014 Toyota Prius, the BRAKE, ABS, and vehicle stability/traction control warning lights illuminated. There was no crash, injury, or noticeable loss of braking before the warnings appeared, and there were no preceding symptoms. The vehicle was evaluated by Mac Haik Toyota in League City, TX, an authorized Toyota dealer. They diagnosed DTC C1391, “Abnormal Leak of Accumulator,” and determined that the brake booster and brake booster pump/accumulator assembly require replacement. The dealer advised that the vehicle cannot be driven and is considered down. The vehicle/components are available for inspection upon request. My safety concern is that this is a brake-system malfunction serious enough that an authorized Toyota dealer has determined the vehicle cannot be driven. Toyota previously established Customer Support Program ZJB addressing internal malfunctions of the brake booster and brake booster pump assemblies in 2011–2015 Prius vehicles. Toyota’s documentation specifically identifies C1391 as a diagnostic code associated with this condition. My Prius has only approximately 102,000 miles, well below the program’s 150,000-mile limitation, but is outside its 10-year time limitation. The Toyota replacement part required to repair the brake system is now backordered with no known timeframe for availability. Because Toyota has advised the vehicle cannot be driven, it will remain out of service until the part becomes available. I am reporting this because a previously identified brake-system failure continues to occur after Toyota’s support period expires. I ask the federal safety agency to consider whether continued C1391 brake booster/accumulator failures in these Prius vehicles warrant further investigation or safety action.

Filed Aug 3, 2026 · Brakes, Electrical · HI

I am submitting this complaint regarding a serious safety concern involving the brake actuator/booster assembly on my 2014 Toyota Prius. My vehicle has experienced failure of this critical braking component and has been unable to be properly repaired since November due to difficulty obtaining the correct replacement parts. This involves a major safety system required for proper braking operation. Brake actuator/booster assembly. Diagnostic codes: B1206, B2321, C1252, C1253 C1256. Toyota previously acknowledged brake actuator concerns through Customer Support Program ZJB. However, my vehicle is outside the program limits despite experiencing what appears to be the same type of failure reported by many other Prius owners. Since November, I have faced difficulty obtaining the correct parts, reports of nationwide backorders or limited availability, conflicting information regarding updated Toyota part numbers, and concerns about repair providers advertising new OEM parts that may actually be aftermarket or incorrect components. This creates a safety concern because owners experiencing brake failures may be unable to obtain timely repairs using verified, appropriate parts. Repair estimates have ranged from approximately $3,000 to over $4,000, including a Toyota dealership estimate of approximately $4,100. This creates a significant barrier to restoring a vehicle to safe operation, especially involving a component Toyota has previously addressed through a customer support program. I request that the federal safety agency review this complaint and similar reports to determine whether further investigation is warranted regarding Toyota Prius brake actuator failures, parts availability issues, and whether additional manufacturer action or support is needed. A vehicle’s braking system is a fundamental safety component. Owners should be able to obtain a safe and reliable repair without months of delay or uncertainty regarding replacement parts.

Filed Apr 15, 2026 · Brakes · MD

On April 5, 2026, while driving downhill around a corner in my 2014 Toyota Prius, the brake booster and brake booster pump assembly failed without any prior warning. When I pressed the brake pedal the car did not slow down and instead appeared to accelerate due to a complete loss of braking assist. I was unable to stop the vehicle normally and had to rely on gravity and coasting to slow down, creating a serious risk of collision. There were no warning signs prior to the failure. Immediately after the incident, three warning lights illuminated on the dashboard: the BRAKE light, the ABS light, and the VSC (vehicle stability control) light, which have remained on since. The vehicle was taken to DARCARS Toyota Baltimore, 6007 Eastern Ave, Baltimore, MD 21224, where the failure was confirmed on April 15, 2026. Technician Victor Lawson diagnosed diagnostic trouble code C1391, which is the exact qualifying code listed under Toyota's Customer Support Program ZJB for brake booster and brake booster pump assembly failure (RO# XXX). The vehicle remains at the dealership and is available for inspection. Toyota corporate was contacted and opened case number XXX but declined to cover the repair despite this being a documented issue that Toyota has publicly acknowledged. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jan 8, 2026 · Brakes · UT

The brake booster system (electric brake booster pump) in my 2014 Toyota Prius has been making frequent, audible cycling noises inside the cabin, particularly during cold weather. I have also noticed a faint odor outside the vehicle that seems related to electrical movement. No ABS or brake warning lights have illuminated, but the cycling pump may indicate increased stress on the brake system. The issue has not yet been diagnosed or confirmed by a dealer or independent service center. The problem has not caused a loss of braking ability to date, but the unusual noises and electrical odor suggest potential risk if the booster were to fail completely. No recall or customer support program currently covers this issue. The component is part of the vehicle’s brake system and would be available for inspection by a dealer or manufacturer upon request. Toyota has offered no help or possibility of Goodwill assistance inspection for this issue.

Filed Jul 3, 2025 · Brakes · HI

I am writing to express my profound concern and disappointment regarding a recent, terrifying incident involving the brake system of my 2014 Toyota Prius. On Saturday, June 21, 2025, while driving with other passengers, my vehicle experienced a complete and sudden brake failure. Multiple warning lights illuminated on the dashboard, and despite my efforts, the brakes became unresponsive, making it impossible to stop the car. The sheer terror and helplessness I felt in that moment, with the very real potential for a catastrophic accident involving myself, my passengers, and other road users, is indescribable. Fortunately, through sheer luck and quick thinking, I was able to make an emergency stop on the side of the road, preventing any collision or injury. However, the emotional toll of that experience, the lingering stress, and the fear of a recurrence remain significant. I was subsequently informed that the cause of the failure was a leak in the brake accumulator. I am attaching the diagnosis and repair invoice. The necessary repairs were not completed until Wednesday, June 25th. This unforeseen and critical malfunction also necessitated the expense of a rental car for four days, adding to the financial burden and inconvenience. My frustration is compounded by the fact that this brake accumulator issue is a well-documented and known defect in Toyota Prius models, specifically affecting 2010-2015 vehicles. Toyota itself has previously issued a Technical Service Bulletin (TSB T-SB-0043-13) acknowledging this problem and offering warranty extensions for affected vehicles, typically up to 10 years or 150,000 miles. Despite this being a recognized safety concern, I was informed that my vehicle falls approximately eight months outside the 10-year warranty period, thus disqualifying me.

Filed Apr 29, 2025 · Brakes · CA

Issue started with a noise sounding like a motor constantly trying to prime its self. Then while driving on freeway ABS light Brake light and traction control lights all came on. Took car to dealership and was given a $3700 bill to replace Brake Booster Master Cylinder and Brake booster pump. This is a known issue to Toyota and have offered an extended warranty 10 years or 150000 miles but not a recall. My vehicle is at 11 years and 123000 miles. This issue put my family in danger due to the threat of total brake failure.

Filed Apr 17, 2025 · Brakes · AZ

Was driving down the road and the brakes stopped working and the the brake light the traction light and abs light came on. The brakes only worked if i put the pedal all the way to the floor after that. I checked online and found numerous other people have had this issue but no recall has ever been done. only the federal safety agency safety notices and a volunteered customer support program by toyota which was no longer being honored because I was passed the 10 year mark even though my vehicle was still under the 150k mile threshold by toyota. I wish your organization would force toyota to do a full recall on this. this is a dangerous safety issue involving a defective brake booster and master cylinder

Filed Oct 12, 2024 · Brakes · FL

On [XXX] my brakes failed while driving, (brake booster and actuator) moving at 25 mph, all of a sudden lights ABS and brakes indicator light started flashing and beep. I was approaching a yellow light and attempting to slow down, my foot went to to floor and the were NO BRAKES. I used the EMG brake slow down me pulled into an empty parking lot. My vehicle is available for inspection at request. My safety was was put at risk due to having no control and coming very close to crashing into another car putting that driver at risks as well, but was blessed I was able to avoid an accident. This problem has been confirmed by Phillips Toyota in Leesburg FL #(352)728-3020. The vehicle components have not been inspected by others besides the dealer. I am 2 months over the 10yr customer support program at 102k miles. I have been complaining for the past YEAR to the dealer regarding strange noises like chirping, air deflating when pressing brakes, constant buzzing sounds from system even when car is off, and being propelled forward when going over gravel or railroad track surfaces of the ABS light goes on. This is on record and each time I’d ask, they’d mention it is the brake booster going but because there was no indicator lights or code coming up, they were unable to do anything. My last service in may 2024, I requested a diagnostic on the brake system, which I paid extra for, knowing the 10yr program was about to be expired in July. The dealer found no codes and assured me it was safe to drive and that if I were to see those warning light come on, that I was to drive the car straight to the dealer to inspect. Well, long story short, the lights came on, and immediately the were NO Brakes and I was completely out of control with no time to drive it safely to the dealer. I had it towed to the dealer and they quoted me $3000 to repair brake booster/actuator. I am working with Toyota corporate for compensation. This is a major safety issue that should be a RECALL! INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION

Filed May 28, 2024 · Brakes · CA

Drove car to work one morning and it was VERY difficult to brake almost causing an accident. Brought it into the Toyota shop and they said this code came up: DTC code C1391: Abnormal leak of accumulator pressure ,recommending to replace brake booster and brake booster pump assembly internal malfunction of components.The necessity of its routine replacement is vital as an old or malfunctioning unit leads to decreased braking performance and ultimately brake failure. They told me that there was a program offered to customers where they would replace this known issue, but I'm 2 months outside of this so the issue is no longer covered under Toyota. The fact that this is a known issue that Toyota does not want to recall is ridiculous and now they want customers to pay for it.

Filed Sep 27, 2023 · Brakes · FL

After I started my car and began driving away from a shopping center, I noticed that there were 3 static warning lights on the dashboard that had not been there before. They were the slip indicator light, the brake light, and the ABS light. I also heard a short, repeating buzzing sound coming from the front of the car that I had never heard before. As I was driving, the brake suddenly felt loose. Luckily, this happened as I was pulling out of a shopping center parking lot, so I was able to pull over to the side of the road instead of getting on the highway, which I was about to do. The following day, a Toyota dealer indicated that the issue was the brake booster pump/actuator system and that my car returned with error code C1391. The dealer indicated that this is a known problem with Priuses within my year range. I was told that I would have to replace both the pump and actuator. After talking to the dealer, I realized that there had been subtle clues of this problem beforehand. In the few months leading up to this incident, sometimes if I hit a big bump in the road, for a moment the Slip indicator light would flash and I would feel like I had no control of the car i.e. I was ever so briefly slipping. However, because this happened so briefly and when I hit a bump and everything went back to normal, I didn't think this was an actual problem, but now I believe this was an early sign of the brake failure. I contacted Toyota Corporate Office. They confirmed that this was an issue known to them with Priuses and said that they had sent letters to the previous owner of the car in 2019 offering an extended warranty not a recall. However, apparently, the previous owner had not fixed the problem and the extended warranty expired. Toyota refused to pay for the repair for this and refused to forward a copy of the 2019 letter to me,. This brake defect is a serious issue with no major warning signs. As of this writing, the part is available for inspection.

Filed Nov 30, 2022 · Brakes · TN

My brakes completely stopped working while driving on a busy road. I took it to Toyota and they said it was my brake booster pump assembly. There is a known issue with the booster pump assembly and Toyota has a program to extend their warranty to fix this, but I was never once notified of this issue and never received any mail or notifications. They refuse to cover the repair because my mileage is out of warranty, despite the fact that this is an issue they caused and I almost wrecked and could’ve died. I was on a very busy road and my car was completely uncontrollable due to the brakes not responding. My passenger, others on the road, and myself could’ve died. The Toyota customer service representatives confirmed that this is part of the “customer service” program and it does not qualify due to it exceeding 150,000 miles. No warnings appeared on the dash until the brakes stopped working. The vehicle was inspected by Toyota and was confirmed to have said issue. This needs to be immediately recalled, I almost got into a very serious wreck.