2012 Toyota Prius brake problems

SERVICE BRAKES

Brake warning lights on, buzzing sound every 10 seconds. Likely a known actuator and master cylinder issue

NHTSA complaint #11750980 — an unverified report by a vehicle owner.

SERVICE BRAKES

Brake lights icons stay on mechanic at Toyota dealership state need new brak master cylinder and booster

NHTSA complaint #11751225 — an unverified report by a vehicle owner.

SERVICE BRAKES

My 2012 Toyota Prius is experiencing brake actuator pump failure, presenting diagnostic trouble codes C1253 (brake actuator pump motor stuck/locked) and C1256 (brake actuator pump motor overcurrent). These codes trigger ABS, brake, and VSC warning lights and disable ABS and stability control. Toyota previously acknowledged this exact defect under Customer Support Program ZJB, which covered 2010-2015 Prius vehicles for brake booster and brake booster pump assembly failures triggered by these specific codes. I am the original owner of this vehicle, purchased new in 2012. I never received notification of CSP ZJB despite being the registered owner at the time notifications were distributed in 2019-2021. My current mileage is under 150,000 miles, within the secondary coverage mileage limit established by the program. Toyota has declined to provide goodwill coverage citing program expiration. This is a known safety defect that reduces braking effectiveness and disables ABS — it should have been addressed through a mandatory recall rather than a voluntary program with an expiration date that left original owners without recourse due to failed notification.

NHTSA complaint #11748062 — an unverified report by a vehicle owner.

SERVICE BRAKES

The power brake unit and actuator are failing.

NHTSA complaint #11744357 — an unverified report by a vehicle owner.

SERVICE BRAKES

Almost had an accident due to the brake master, actuator and booster pump assemblies, failing. There were no warning lights alerting me to an issue. Just lost ability to break and car shut off completely while in motion.

NHTSA complaint #11740616 — an unverified report by a vehicle owner.

SERVICE BRAKES

The brake booster and brake booster pump assembly (also referred to as the Accumulater or Accentuater) have failed in my vehicle the same as Toyota's known defect that was mentioned in their Customer Support Program 20TE07 (part numbers can be found within the filing of their CSP 20TE07). I am reporting that this issue appears to have affected more than their initial estimate of ~118,960 states impacted vehicles.l because Toyota is declaring my vehicle is outside of their CSP 20TE07 although their defect endangers my safety (and the safety of others) and attempts to put their defective vehicle brake parts as my financial burden. This issue should have been/should be a larger recall. Thank you.

NHTSA complaint #11736344 — an unverified report by a vehicle owner.

SERVICE BRAKES

2012 Prius with 174,344 miles in great condition, with regularly scheduled oil changes. ABS/Break Actuator failure on freeway with no warning other than a beep a few seconds before the breaks disappeared completely. Break pads changed 4 months ago and new wheels installed as well. This is a known problem with Toyota under the TSB002419 where Break booster actuator was put on a customer service program to be fixed by the dealerships, but has since expired since 2022. The cars are still known to have their breaks go out due to this malfunction but it is now not covered by Toyota and cost $4K-$5K to fix which is more than the market value of the car today. This needs to be fixed and regulated.

NHTSA complaint #11734136 — an unverified report by a vehicle owner.

SERVICE BRAKES, HYDRAULIC

The contact owns a 2012 Toyota Prius. The contact stated while driving at an undisclosed speed, several unknown warning lights illuminated, with an abnormal sound coming from the vehicle. The vehicle was taken to the dealer where it was diagnosed with brake booster failure. The contact was informed that the brake booster pump needed to be replaced. The vehicle was not repaired. The contact stated that the failure was a known failure with the vehicle. The manufacturer was made aware of the failure. The contact was informed that an undisclosed Extended Warranty Program had expired. In addition, the contact was informed that the repair was not covered. The failure mileage was approximately 175,000.

NHTSA complaint #11722029 — an unverified report by a vehicle owner.

SERVICE BRAKES

My Brake Booster/Actuator failed on me while on the freeway with out any warnings. It made it really hard to stop the car. I didn't find out what it was untill I took it into a repair shop and they told me it was the Brake Booster/Actuator.

NHTSA complaint #11719694 — an unverified report by a vehicle owner.

SERVICE BRAKES

The vehicle is experiencing a suspected brake actuator / brake booster failure. Multiple warning lights appeared simultaneously, including ABS, Brake, Traction Control, and Master Warning lights. The vehicle produces a frequent buzzing noise from the brake system, especially at low speeds or when stopped. The noise occurs repeatedly when pressing the brake pedal, indicating the system is struggling to maintain hydraulic pressure. This condition raises serious safety concerns because it may reduce braking performance and increase stopping distance. Brake system failures present a significant risk to vehicle occupants and others on the road. After researching the issue, I learned this appears to be a common failure in Toyota Prius vehicles of similar model years, and Toyota previously issued extended warranty coverage for the brake booster/actuator assemblies. However, many vehicles now exceed the coverage limits despite the safety nature of the defect. I am submitting this complaint because a failing brake system is a critical safety hazard, and this issue appears widespread.

NHTSA complaint #11717956 — an unverified report by a vehicle owner.

SERVICE BRAKES

Vehicle check engine code C1391 (Antilock Brake System - abnormal leak in accumulator) came up on 2/5/2026. Recommended repair is to replace the Brake Booster Pump and Assembly, Brake Booster - over $1000 in parts alone. This WAS covered by an Extended Warranty by Toyota (10 years / 150K miles). I only have 120K miles at this time but am past the 10 year mark. However, it seems that this part will fail in every Prius given time and encourage NHTSA to monitor these failures and hold Toyota accountable to address post the 10 year / 150K mile mark.

NHTSA complaint #11716476 — an unverified report by a vehicle owner.

SERVICE BRAKES

Vehicle: 2012 Toyota Prius Mileage: Approximately 217,000 miles While driving normally in traffic, the vehicle experienced a sudden and unexpected brake system failure. Multiple warning lights illuminated simultaneously, including the red BRAKE warning light, ABS warning light, traction control light, and warning symbol (!). Shortly after, the vehicle began emitting an audible warning/beeping, and there was a sudden loss of power brake assist. The brake pedal behavior changed abruptly: the pedal became very soft initially, then became suddenly hard halfway through travel, This failure occurred while approaching another vehicle in traffic, and I narrowly avoided rear-ending the vehicle in front of me. The unexpected loss of brake assist created an immediate and dangerous situation, as the vehicle did not decelerate as expected when the brake pedal was applied. Due to the seriousness of the brake failure and safety risk, the vehicle was removed from service and towed. This incident represents a critical safety defect, as sudden loss of braking assist while driving poses a significant risk to vehicle occupants and other road users. I am reporting this incident to document the hazard and request investigation into the reliability and safety of the brake system design. I am requesting you to please issue a recall and reimburse me , as these parts are very expensive , it affected my financial situation, Thanks

NHTSA complaint #11713170 — an unverified report by a vehicle owner.

SERVICE BRAKES

My 2012 Toyota Prius plug in hybrid had just passed state inspections and was even looked at by a dealership a year ago with no reported issues. I brought up a whirring issue at the dealership when breaking but the dealership said that’s normal for a hybrid. In a matter of minutes while driving, the traction light, brake light, and ABS light came on as well as a groaning, whirring sound when breaking. Over time, the breaks failed and I could not stop the car, almost causing a wreck because I could not stop without putting all my body weight on the break pedal. When taking it to the Toyota dealership for a whole diagnostic, they said it was a break actuator and break booster failure that is known to happen with Prius’s. They quoted me $3000 for a repair and then marked my breaks as yellow not red on their sheet implying I could still drive it despite the dangerous situation of driving without functioning breaks. When looking into it, this seems to be a known and common problem with Prius’s due to a faulty manufactured part. Codes were c1391, wc1256, and c1252. I believe this part should be recalled and Toyota should fix these faulty parts, especially considering they inspected my car and did not mention it as an issue despite it being a known issue. I got a second opinion from Mavis Tires and they concurred with the diagnosis but could not fix it.

NHTSA complaint #11707166 — an unverified report by a vehicle owner.

SERVICE BRAKES

While driving, the vehicle experienced a sudden brake system malfunction without prior warning or gradual degradation. The vehicle was being operated under normal driving, road, and weather conditions. No recent brake service, repairs, or aftermarket modifications had been performed prior to the failure. Multiple warning lights illuminated on the dashboard, including the ABS warning light, brake warning light, and traction control warning light. Shortly after the warning lights appeared, the vehicle began emitting continuous warning beeps. Audible buzzing or pumping noises were also present from the brake system during the malfunction. During this event, brake performance was reduced and braking felt inconsistent. The brake pedal became hard at times and spongy at other times, requiring increased effort to slow the vehicle and resulting in unpredictable braking response. This created a safety concern while the vehicle was in motion. The driver was forced to alter driving behavior and exercise extreme caution due to reduced braking confidence and unpredictable pedal feel. The malfunction has occurred intermittently during normal driving. The condition temporarily resolves on its own and later reoccurs without corrective action. The suspected failed component is the brake actuator / ABS actuator assembly. A diagnostic scan retrieved fault codes C1252 (Brake Booster Pump Motor ON Time Abnormally Long), C1253 (Pump Motor Relay Malfunction), and C1256 (Accumulator Low Pressure), which are consistent with brake actuator malfunction. The failure occurred at approximately 154,000 miles. This vehicle model and generation have a documented history of premature brake actuator failures with similar safety-related symptoms reported by other owners. The condition places the driver and others at risk due to unpredictable braking behavior, reduced braking effectiveness, and repeated warning alarms while driving. Warning lamps and audible alerts continue intermittently.

NHTSA complaint #11707029 — an unverified report by a vehicle owner.

SERVICE BRAKES

While driving on a city road below the speed limit, braking was compromised leading to loss of traction and failure of the ABS system. During the incident, the brake, ABS, and engine warning lights all turned on and a collision was only avoided due to pumping of the brakes. Further investigation by a mechanic revealed a failure of the brake actuator system. Failure of this system has increased the stopping distance of the vehicle considerably and makes braking unreliable and unpredictable.

NHTSA complaint #11701919 — an unverified report by a vehicle owner.

SERVICE BRAKES

While driving 60 mph in highway, ABS, traction control and brake lights lit up and vehicle lost its effective braking power. There were no prior warnings prior to this failure. It was a sudden incident. Since it wasn't rush hour, I could safely reduce speed and bring the car to stop. Situation could have been much different if it was normal hours. After taking the car to dealership, it indicated DTC code 1391, Brake Assembly Failure. The car was fixed at dealership at cost of $3,000. When researched further, it appeared that there is broader pattern of failures. Numerous reports have been made by owners of 2010–2015 Toyota Prius, Prius PHV, 2012–2015 Prius V, 2012–2014 Camry Hybrid, and 2013–2015 Avalon Hybrid vehicles, all of which share the same brake booster pump assembly design manufactured by Advics Co., Ltd. Dealerships, including Capistrano Toyota and Claremont Toyota in California, have previously petitioned NHTSA regarding this very defect. Their 2019 letter to the agency documented that Toyota: * Knowingly excluded hundreds of thousands of hybrids from prior safety recalls (DOH 13V-235 and KOL 19V-544) despite identical failures. *Issued “post-failure” repair programs (Warranty Enhancements ZJB, ZKK, ZKC, ZLM, 20LE03, 23TE06 and 23TE07) only after owners experienced brake failure. * Identified the same DTC codes (C1252, C1253, C1256, C1391, U0293) in both recalled and unrecalled vehicles—codes that correspond to accumulator leaks, loss of brake pressure, and failure of brake assist and stability control systems. * Admitted through Technical Service Bulletin TSB-0130-19 that these defects caused loss of hydraulic pressure, increased stopping distance, and total loss of brake assist in affected hybrids. In short, the defect pattern across multiple hybrid models is identical to those already recognized by Toyota and NHTSA under prior recall campaigns, but for reasons unexplained, Toyota limited the recall population and left many consumers unprotected

NHTSA complaint #11696848 — an unverified report by a vehicle owner.

SERVICE BRAKES

Traction control.Abs and brake warning lights all came on.

NHTSA complaint #11696581 — an unverified report by a vehicle owner.

SERVICE BRAKES

2012 Toyota Prius. The brake system malfunctioned and my daughter was almost in a wreck. The ABS, traction control, and brake warning lights on the bashboard all illuminated at the same time. The brake pedal feels soft and is less responsive requiring more effort to stop the vehicle. The brake actuator assembly is making a hissing noise. Ran a ABS test using a scan tool and received a C1391 error code. The Code points to a leak within the brake actuator system. Upon research I have found that this is a very common and costly repair that Toyota has known about for many years. Toyota issued a customer support program related to this issue that ran for 10 years or 150,000 miles from the vehicle's date of first use. This car, being a 2012, is beyond the support program. I contacted Toyota, hoping they would do the right thing and cover the repair. I was told that they would not cover the repair or supply the parts to cover the repair. I told the Rep. for Toyota that I did not feel like it was fair for Toyota to continue to put millions of drivers at risk for a product that they clearly realize for years now is defective and could hurt or kill someone. The code and the braking issue did not appear until after the customer support program ended and therefore we had no warning or way to anticipate this braking issue or the danger to my daughter and anyone else riding with her in the car or on the roadway near her travel routes. I traveled 300 miles, rented a Uhaul car tow trailer and brought the car back home. My mechanic confirmed the code C1391 and the fact that the brake actuator has failed. The mechanic has ordered the parts (the same defective parts) to replace the broken ones. Toyota is still selling the same part as a replacement part clearly knowing that it is not safe and no warning came with the replacement part explaining the potential for a braking issue. Based on internet research this same part is in many 2005 to 2013 Toyota and Lexus

NHTSA complaint #11689732 — an unverified report by a vehicle owner.

SERVICE BRAKES

Brake getting stuck on the floor would have to press on brake really hard just to get a response, this will happen out of the blue! Driving in highway or just driving off the driveway. I almost hit a car in front of me due to lack of brake, i had to swerve to the side! First appear 1 day after buying the car..This issue needs to be worked on right away.

NHTSA complaint #11676307 — an unverified report by a vehicle owner.

SERVICE BRAKES

While driving on the freeway I applied the brakes and the brakes suddenly felt soft and not very responsive. At that moment 3 dashboard lights turned on: ABS, BRAKE, and the slip indicator lights. I carefully got out of the freeway, parked the car, and had the car towed to an independent mechanic. The mechanic detected brake booster and actuator problems, code C1391.

NHTSA complaint #11675051 — an unverified report by a vehicle owner.

SERVICE BRAKES

C1391 - Abnormal Leak in Accumulator

NHTSA complaint #11668479 — an unverified report by a vehicle owner.

SERVICE BRAKES

My Prius, along with the thousands of others this has apparently happened to according to a quick online search, has had the C1391 code appear, indicating a failed brake actuator and accumulator. It, like the thousands of Priuses from this generation, have had these faulty brake pump systems develop a leak and begin to fail. You will hear a whirring and hissing noise constantly when it starts going out, eventually resulting in a Christmas tree of dash warning lights and reduced braking due to a failsafe kicking on. Toyota apparently issued a "customer service bulletin" that is now ineffective as it only covered if you had the system fail within 10 years of manufactor or 150,000 miles AND had the codes appear. Most people's Priuses go out AFTER this, unless you're driving it like you stole it. It is a hefty repair too, being quoted at over $3000 at the Toyota STEALSRSHIP!! I have since gone to an independent mechanic and had one portion replaced in hopes that would fix the issue, but it turns out both the actuator and accumulator are needed to be replaced, which is extremely expensive, more so for the actuator than the accumulator, but still exorbitantly expensive. In conjunction with this, Toyota further added difficulties by making their paet numbers they have listed different from the mark number engraved on the part, so buying third party is made a bigger hassle by this as they will not know for certain the part number. This is a huge safety concern as this affects the vehicle's ability to brake. Their service bulletin was the equivalent of offering people bandaids years before they'd be anywhere to getting a cut!! Please investigate and please please PLEASE lead to Toyota issuing an actual recall, regardless of miles or year from manufacture. More and more Priuses are reaching the time where this will occur and it's a huge safety concern, if not an environmental concern when people start disposing of Priuses due to this massive failure with hefty repair bills.

NHTSA complaint #11665925 — an unverified report by a vehicle owner.

SERVICE BRAKES

The brake booster and brake booster pump assemblies had to be replaced at the dealership. Parts are not available for inspection as far as I know. We were warned by the dealership that we should not be driving the car because the brakes could completely fail at any moment if we didn't have parts replaced. That would have been dangerous for us and anyone else sharing the road with us. On a Sunday, leaving our house and driving down our street, three lights turned on on the dashboard display - traction, brakes, and ABS - and the brakes felt softer and less responsive than normal. After having gotten a diagnosis and repair estimate from the dealership, we carefully drove the car home to consider our options. We tried to get a second opinion from a trusted mechanic, but it sounded like the parts we needed were tightly monitored by Toyota and the original estimate for the repair from the dealership was above $3,000. After a few days, the dashboard warning lights turned off and the brakes felt back to normal. The whirring noise which had been happening roughly every 4 seconds had slowed to roughly every 10-12 seconds. We were told that this turning off of the lights sometimes happened, but that the issue was still the same. Prior to these lights turning on, the car had been making a lot of the whirring noises for some time, but it had never thrown the codes before that would have been picked up by a mechanic. At the time, we didn't recognize the sounds as a sign of an impending commonly recognized failure - only after doing some research did we find that this was a very common problem for a lot of Prius owners, especially for the given year and number of miles we had. There is an "extended warranty" for this part and repair, but while we were within the mileage limit, we were outside of the time limit and we were told at the dealership that Toyota would be inflexible about paying for the repairs.

NHTSA complaint #11665104 — an unverified report by a vehicle owner.

SERVICE BRAKES

While driving my 2012 Toyota Prius, the traction control, brake, and ABS warning lights all came on at the same time. I used a home OBD scanner but it didn’t show any diagnostic codes. After some research and inspection, I discovered that the issue was related to a faulty brake booster and accumulator—something I’ve learned is a common problem with this model. I was relieved to hear that Toyota has an extended warranty on these parts. However, last night while driving, the brakes suddenly stopped functioning properly. It became very difficult to slow down, which put me in a dangerous situation. I’m deeply concerned about the safety risks this defect poses and believe this issue deserves further attention.

NHTSA complaint #11663086 — an unverified report by a vehicle owner.

SERVICE BRAKES, HYDRAULIC

The contact owns a 2012 Toyota Prius. The contact stated while driving 30 MPH, the ABS and traction control warning lights illuminated. The contact stated that while attempting to depress the brake pedal, the vehicle hesitated while responding. The contact stated that there was a buzzing sound coming from accumulator pump. The dealer was contacted. The contact stated that the failure had occurred on several occasions. The vehicle was taken to Nico's Auto Repair where it was diagnosed and determined that the brake booster and accumulator assembly needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure but offered no assistance. The approximate failure mileage was 140,000.

NHTSA complaint #11661457 — an unverified report by a vehicle owner.

SERVICE BRAKES

I am reporting a sudden and dangerous failure of the brake booster in my 2012 Toyota Prius. While driving, I experienced a loss of braking power, accompanied by several warning lights including ABS, Brake, and the Traction Control system. The brake pedal became extremely stiff and unresponsive, significantly increasing the stopping distance. This failure nearly caused an accident, as I was unable to stop quickly enough when traffic slowed unexpectedly. This issue happened without warning and is a serious safety risk. I later discovered this is a common and widely reported defect in 2010–2015 Toyota Prius models. Toyota issued an extended warranty (Customer Support Program ZE3) to cover this known brake booster defect — but only for vehicles within 10 years or 150,000 miles. While my Prius has well under 150,000 miles, it is just over 10 years old, which disqualifies me from coverage, leaving me with a repair estimate over $4,000 for a well-documented manufacturer defect. This seems grossly unfair, especially for responsible owners with low-mileage, well-maintained vehicles. Toyota’s refusal to issue a formal recall and instead offering only limited support puts millions of Prius drivers at risk. A brake system failure of this kind should qualify as a safety defect and trigger a mandatory recall, not a quietly limited program with arbitrary expiration dates. I urge NHTSA to investigate this issue further and consider a recall of the defective brake booster system in these Prius models to protect public safety and ensure fair treatment for affected owners. Thank you.

NHTSA complaint #11661320 — an unverified report by a vehicle owner.

SERVICE BRAKES

This Prius Hybrid is my [XXX] mother's car which she got thinking is was a very safe and reliable vehicle. She purchased the vehicle from a Toyota dealership here in Maine on [XXX]. Last week while driving down the road, all of a sudden, every brake warning light lit up the dashboard and the brakes became extremely unresponsive. It scared us both to death but thank goodness, I was driving when this happened. After doing some research, I have discovered that this a very well known brake issue with the 2010-2015 Prius cars. I cannot for the life of me understand how this major safety defect has not been made into an actual safety recall. I did contact Toyota customer service and they will not help us at all. Even though my mother has only had the car for just under 9 years and is well under the allotted mileage, they said their Customer Support Program (ZJB) only covers 10 years from the day the car was first driven after production. Her Prius now is inoperable and the repair costs are in the thousands. We are so incredibly disappointed with Toyota and the safety board for allowing this to happen to all of the defective Prius owners. I hope you will reconsider and do the right thing and recall these cars before someone does get into an accident where they are injured or killed. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11661343 — an unverified report by a vehicle owner.

SERVICE BRAKES

Brake booster failures are a common safety issue with 2012-2015 Toyota Prius' this one included is starting to fail which can lead to ABS deactivating and shorter braking distances. There was a recall for this part but most tend to fail after the warranty period. Leaving many vehicles unrepaired and dangerous.

NHTSA complaint #11659408 — an unverified report by a vehicle owner.

SERVICE BRAKES

My brakes began making a funny noise when I used them. I only have 80000 on the car and do regular maintenance. I took it in because it seemed the brake pedal was getting spongy as well. They ran in through diagnostic tests and determined the braking module or brake booster/master assembly was bad. This seems to be an issues with Toyota and should be addressed immediately. It is an expensive fix for a low mileage car

NHTSA complaint #11657442 — an unverified report by a vehicle owner.