2014 Toyota Prius Brakes Problems

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)

While driving, three warning lights suddenly appeared on the dashboard . Abs warning, traction light, and break warning light At the same time, the brake pedal became very hard to press, and the vehicle did not slow down as expected. This caused a significant increase in stopping distance, and I nearly rear-ended the vehicle in front of me. The issue appears to involve the braking system and created an immediate safety risk. No prior warning signs were noticed before this incident. The vehicle has not yet been inspected but is available for inspection upon request.

Subject: Brake Booster/Pump Assembly Failure – Toyota Program ZJB / 23TE07 Description of Incident: I am reporting a failure of the brake booster and pump assembly on my 3rd Generation Prius (82,000 miles). While the vehicle is 11.3 years old, it is well under the 150,000-mile threshold of Toyota’s Customer Support Program ZJB. The brake pump began cycling every 13 seconds, indicating an internal pressure leak in the accumulator. This is a documented precursor to a total loss of power-assist braking. Despite the clear mechanical failure, no warning lamps or Diagnostic Trouble Codes (DTCs) were triggered, creating a safety hazard where the system could fail without prior electronic notification. Repair and Cost Details: Because the vehicle was 1.3 years past the arbitrary 10-year "Secondary Coverage" window, I was forced to pay $3,461.18 out-of-pocket for a known manufacturing defect. I would like to highlight a discrepancy in labor billing: while Toyota’s own technical bulletins (ZJB/23TE07) state the repair should take approximately 5.3 hours, the dealership charged 8.9 hours of labor for the same procedure. Safety Concern: By limiting coverage to 10 years, Toyota has left many low-mileage owners with a critical safety defect that degrades over time regardless of mileage. I request that the NHTSA transition this from a "Customer Support Program" to a formal Safety Recall to ensure all affected vehicles are repaired and owners are reimbursed, regardless of the vehicle's age.

The contact owns a 2014 Toyota Prius. The contact stated that while driving at an undisclosed speed, the vehicle failed to slow down as intended with the brake pedal depressed. The ABS warning light was occasionally illuminated. The vehicle was pulled over to the shoulder of the roadway and restarted. The vehicle was taken to a local independent mechanic, where it was diagnosed, and determined that the brake master cylinder, brake booster, and brake lines needed to be replaced. The local dealer was contacted; however, the vehicle was not diagnosed or repaired. Upon further investigation, the contact related the failure to an undisclosed recall; however, the VIN was not included in the recall. The manufacturer was notified of the failure. The contact was referred to the NHTSA Hotline for assistance. The failure mileage was approximately 152,000.

Vehicle: 2014 Toyota Prius v Hybrid Mileage: 79,000 miles The vehicle experienced sudden failure of the brake booster / brake accumulator system. Multiple warning lights appeared including ABS, traction control, and the red brake warning light. Diagnostic code C1391 was retrieved. The brake pedal became soft/spongy and the electric brake pump began cycling frequently. Braking performance felt reduced and inconsistent, creating a potential safety risk. This vehicle has very low mileage (79,000 miles) and has been well maintained. The failure appears to be related to a known defect in the Prius braking system. Toyota previously issued Customer Support Program 20TE07 addressing brake booster and pump failures on 2012–2014 Prius v vehicles. Despite this known issue, the repair is not being covered and the cost quoted is several thousand dollars. A failure of the brake booster/accumulator system significantly affects braking performance and should not occur at this mileage. This appears to be a widespread issue affecting Prius vehicles and represents a potential safety defect involving the braking system.

The slip notification, abs, and brake lights turned on while driving on the highway. The brakes then became very stiff and the vehicle did not brake as fast or as well as it normally does without the lights.

The brake booster/accumulator failed on my vehicle. This part was a common failure during the 2010-2015 production run so much so that Toyota extended coverage to replace. Mine failed recently beyond the warranty extension of 10 years/150k miles. My vehicle has only 108k miles and is 15 months beyond warranty. Toyota Corporate will not replace this vital part, despite the fact it was a defective design. I can’t drive it any longer since I don’t have the $4000 to make repair. Toyota Corporate has shown little concern despite this critical safety defect.

2014 Prius HB with 135k miles , onboard system warning lights for Brakes, ABS system, TPMS and Traction Ctrl all came one suddenly. Brake losing pressure while vehicle making strange noise under front driver side

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.

I was driving on the freeway, and a few lights(including ABS, brake lights) all came on and a beeping noise started, as i immediately lost complete control of my brakes! That God it was late, and no cars were in front of me. The car slowed down as I removed my foot of the gas right away. I tried to pull over as soon as I heard the lights, and that’s when I realized my brakes were completely gone! I was able to stop after about two miles; car stop on its own as it slowed down. Apparently, this was a major known issue and had warranty up to 150k miles. At the time of the incident, my car had about 165k miles. I had the car for years, and no one at the dealer ever mentioned anything about this or even tried to make me aware of it! I called the Toyota dealer and corporate number several times and they declined providing me with any help at all! This caused me fear and traume because I never thought this was possible! It could’ve ended my life and the life of people around me if there were any cars in sight! The problem has been confirmed by a reputable mechanic! He did the repairs! He also called the Toyota dealer and corporate and attempted collecting anything since he found out about the warranty and common issue. They also denied help. No lights were on at all before this incident happened! It all came at once! I even have all records of monthly/ bimonthly complete inspections at the dealer with everything normal on the results!

My 2014 Toyota Prius (VIN [XXX] , 77,000 miles) displayed Brake, ABS, and Slip warning lights. A mechanic confirmed failure of the Brake Booster and Pump Assembly (DTC C1391). Toyota previously acknowledged this as a safety-related defect under Customer Support Program ZJB, but my coverage expired because I never received Toyota’s notice dated May 21, 2019. My car has been undrivable for weeks and Toyota refuses goodwill repair. This is a serious brake safety issue that should be reviewed for recall or extended coverage since many Prius owners have experienced the same failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My brakes consistently lock and the car lunges forward. Driving down the highway I tapped my brakes and they didn’t work. I lost traction in the brakes. I had no control over the car or speed. I’m scared everyday I have to drive it. This is extremely dangerous and I've seen this comment often with this vehicle. Toyota said they had an extended warranty for this but it expired. I never received any mail or phone calls stating that this was a known defect. They say they can’t do anything now and are quoting me over $3000 to fix it.

The ADS, traction light, and brake light all came on at once. Apparently this is a known problem with these cars and Toyota was fixing them for awhile but has stopped. No brake issues were reported when I brought it in for inspection in 2023. I never received any mail stating that this was a know defect and I needed to bring my car in to get it inspected. It's obvious to me that Toyota designed a defective part that impacts safety, and is forcing the owner to bear the cost of the fix by creating parameters that can never be met before the warranty expires.

The brake actuator failed, it can be available for inspection anytime. My ABS light, brake light, and traction control lights all came on to indicate the failure. Since the hybrid engine requires the breaking system to recharge, failure of this part will eventually lead you to be stranded if it isn’t functional. Additionally, the responsiveness of the breaks makes driving at higher speeds a lot riskier. Toyota offered an "extended warranty" to have the parts replaced for free for 10 years or 150,000 miles, whichever came first. My make is 2014, at only 89,000 miles.

Apparently Toyota knows of a recurring problem with the brake actuator. I took my Toyota Prius to the dealer for an unrelated recall issue that they repaired and I asked them what the sound was that I kept hearing every 10 seconds or so. The told me it is the brake actuator, but did not seem concerned at all that I get it repaired right away. They did quote me a very high price to have it fixed by them. I have chosen to take it to my mechanic for repair. In the mean time, I decided to research this on the internet and discovered that it is a known problem by Toyota and there is a class action suite filed on them. I want Toyota to pay to have it fixed! I fear for my life and lives of others with the same issue.

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.

2014 Toyota Prius C with 220k miles. Four warning lights came on while driving. Brakes became not responsive unless you press down very hard. Regenerative braking, went away. The Brake pump can be audibly heard turning on every few seconds.

After 120K miles and 11 years of use, my Prius 3 brake booster pump failed while I was driving. The warning lights came on, including the ABS and brake lights. My brake felt strange, and I had to finish my drive to the dealership keeping a large driving distance so the brakes would work in time. I was advised that this was a result of a C1391 error and that the brake pump part is only covered under extended warranty for 10 years. The advisors at the dealership said it is extremely common for cars to come in with this problem just after the warranty period has ended. I have spoken to other Prius user who have complained of the same issue and are considering a class action lawsuit because this safety issue is so common.

See Attached Letter

While driving my dashboard lit up with Brake, ABS, and traction control warning lights. Brake pedal fell to the floor when pressed. I was then able to stop the car. I brought the car to a local auto parts store, where they were able to determine that the error code was C1391 brake accumulator pressure leak. I made an appointment and brought my car to my local Toyota dealer the next day. I was informed that the brake booster assembly, brake booster pump, and master cylinder would have to be replaced, at a cost of approximately $4035.00. I was informed that Toyota issued a Customer Satisfaction Program for this exact issue on my car. While my car has 129,000 miles and falls within their coverage range of 150,000, the car’s age of 11 years did not fall within their limit of 10 years. According to Toyota, this is a known failure and my only problem is that my brakes did not fail sooner. Toyota’s corporate office denied my appeal to cover the cost of the repair. The local Toyota dealer charged me $150 to read the code and confirm what the local Auto parts store was able to do for free.