2012 TOYOTA PRIUS Service Brakes Problems

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.

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...

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.

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...

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...

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...

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.

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...

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

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...

While pulling out of a parallel parking spot going slightly uphill, I braked as I looked around the back of a double parked truck. I saw a car coming, braked hard, and suddenly my car surged forward across the street and hit a parked car. I looked down and saw that my foot was squarely on the brake pedal pressing down as hard as I could. The parked car was unoccupied, and I was uninjured. There were no warning lamps, messages, or other symptoms of the problem. I turned my car into the dealer for repairs and a fix to the sudden unexpected acceleration. They could offer no fix until a Toyota representative examined the car. On August 14, by an emailed letter, Toyota claimed it found no defects and it must be the result of driver error, specifically, my mistakenly hitting the accelerator. This is gaslighting denialism. (a) The...

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.

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.

C1391 - Abnormal Leak in Accumulator

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...

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...

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.

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...

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,...

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.

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

47050-47180 47070-47060 Both failed at same time along with many others getting quotes of 3500-4000 to replace no brake control or anti lock brakes

Toyota installed known faulty brake booster and master cylinder systems in Prius C models manufactured 2012-2014. Knowing these systems would fail, but not wanting to pay for their mistake, they created a basically secret "extended warranty program" for owners to get their brake booster replaced ONLY IF for a specific 2 year time frame their brakes failed with a certain DTC code. Knowing that many prius owners would not actually receive the notification nor had driven their vehicle enough miles for the braking system to fail, they got away without having to correct their issue. The brakes literally just fail and stop working in the middle of the highway, causing extreme safety concerns and accidents with no responsibility from Toyota.

Brake system went out suddenly making the car brakes not work

Subject: Safety Complaint – 2012 Toyota Prius Brake Booster Failure (C1391 Code) I am writing to formally report a serious safety defect in my 2012 Toyota Prius involving the brake system. Recently, my vehicle’s dashboard displayed the ABS, traction control, and brake warning lights, indicating a critical braking issue. Upon diagnostic testing at a Toyota dealership, the vehicle was found to have DTC Code C1391 – Brake Booster Leak/Accumulator Failure. I later discovered that Toyota acknowledged this defect and issued a Customer Support Program (CSP) to cover repairs. However, I was never notified, despite always servicing my vehicle at Toyota dealerships. When I contacted Toyota, they confirmed that my vehicle has been flagged in their system, yet I was never received anything in the mail about the potential brake failure. Toyota initially set the CSP expiration in 2023, later extending it to May 2025, but they have refused to repair...

My break actuator goes off every 12 seconds continuously. There is no warning sign in the dash board. Brought the vehicle to the Toyota dealership and had it checked out. The dealership says there is no problems according to their analysis. But the actuator continuously goes off every 12 seconds and the dealership said this was "normal" and charged me the service fee. I am seriously concerned because I drive this car with my child and I am reading that this is a bad sign and that the breaks might fail at any time. Since the dashboard doesn't give me a warning sign and the dealership says there's no problems based on their diagnostics, even if everyone can hear the actuator go off ever 12 seconds I guess I can safely drive this vehicle...it seems like driving a ticking disaster waiting to happen.

ABS pump and master cylinder malfunction. Pump is running very often. Hard braking makes it sound abnormally.

Brakes failed

I accidentally slid out into traffic as my brakes failed as I pulled up to stop at the edge of the parking lot. I was nearly hit driver's side on a pickup. Fortunately, it was able to swerve around me and there was no immediate following vehicle. I was able to pull out and back into a nearby parking lot to address the problem with my brakes. Upon speaking to my mechanic and local Toyota Dealership I was informed that the brake booster/accumulator had failed and that this was a known issue on my vehicle. Toyota extended a special warranty on these parts several times but did not notify owners of the safety risk. That warranty coverage has expired for my vehicle. I believe it is an inherent safety risk and they obscured it by covering the parts under this extended warranty. I believe they should be recalled and at...

Failure in ABS system

Vehicle has good break pads and rotors. Also the vehicle turn on the ABS the Break and the slippery lights on. When the car was scanned is show code C1391" which indicates a problem with the brake accumulator within the system, often requiring replacement of the brake booster and accumulator assembly. I can't drive the car and other people with same car on 2011 year has the same issue

As i was driving, my breaks suddenly became spongey and unresponsive. I could hear a "hiss" sound come from below me. ABS and other warning lights came on on my dash. As i was near my auto mechanic i tried to make it there safely, and as i drove the brakes seemed to become softer and softer. By the time i had reached my mechanic i was so uncomfortable with its ineffectivness i felt it necessary to use the emergency brake to come to a complete stop. My mechanic confirmed that the issues included the failing of the Brake Booster, Brake Master Cylinder, Accumulator Pump, ABS, ABS Computer. According to him this was caused by a set of issues involving internal leaks in the brake booster assembly. These issues were replicatable, and my mechanic says they pose a saftey risk. Even after he gave it a "temporary patch job." Due...

My Brakes almost caused me to crash on Jan 18th. I'm driving down the highway and traffic comes to a complete stop. I started braking but my abs, stability control and brake light come on. When this occurred I had to push the brakes to the floor just to stop. My brakes were very unsafe and unpredictable. I had to drive way below the speed limit to make it home, keeping at least 8 car lengths between me. I inspected the vehicle when I made it home. Their is noise coming from the driver side firewall. Something is consistently turning on and off and a slight click after each cycle, every 5 seconds approximately. I was told that it was my abs pump or brake actuator. This is unacceptable and dangerous to all consumers. The fact there was no warning that occurred in a safer environment. I'm so thankful my...

I am writing to bring attention to a critical safety issue affecting the 2012 Toyota Prius and other Toyota models equipped with the brake booster and actuator system. These components are failing at alarming rates, leaving vehicles with no functional brakes, ABS, or traction control. Additionally, this failure compromises the hybrid system due to the regenerative braking no longer working, potentially causing further damage to hybrid components and resulting in repairs costing several thousand dollars. Toyota issued Customer Support Program ZJB, which covered these issues for a limited period. This program was in effect from August 31, 2021, with no mileage or year restrictions, but offered secondary coverage for up to 10 years or 150,000 miles from the vehicle’s first use. Unfortunately, my vehicle, with approximately 130,000 miles and 12 years of age, was denied coverage when brought to a dealer after the program had ended. Despite the brake booster...

The brake actuator has failed in this 2012 Prius with 135,000 miles. No issues were noticed while braking, however, when starting the car, the ABS, Brake and Traction Control warning lights lit up. The Toyota Dealership said this is a failed Brake Actuator and quoted $3,800. We have learned there is a secondary warranty on this part due to constant failures that Toyota issued, however, this warranty only applies to Prius up to 150,000 miles or 10 years from initial use, whichever comes first. This is unfair to most Prius users as this is a common problem happening, but typically happening after the 10 year mark.

The ABS, Brake, and Traction Control lights all illuminated while driving. I took it into a local shop, the computer scanned "brake accumulator leak". The accumulator is buzzing every 10 seconds and the brake fluid needs topping up. Now there is a brake fluid puddle under the car. The fix is to repair the brake master cylinder and replace the brake booster pump. The car is a 2012 with 110,000 miles. This is a known Toyota Prius vehicle issue but they decline to service it and can the brakes can fail.

Without warning, the ABS, Traction Stability, Brake and other lights lit up and I lost braking on the highway. Luckily, I was in very light and narrowly avoided a crash. I was able to get home with far less braking power and no regenerative braking. Since then, I have researched the problem and found that this is an extremely common issue. I can remedy it for ten or twenty minutes by putting the car in DIAG mode and pumping the brakes, but it will do it again, and again. I need a new accumulator and ABS module, and the dealer wants thousands for it. I cannot afford it and it is a known flaw and a safety issue. I take my daughter to school in this car, thankfully it's nearby, but it's terrifying. Our other Prius has no issues, and I understand that Toyota has repaired other cars under a...

2012 Prius in very good condition with 180k miles- only 12 years old. Driving on back roads (thankfully) and the drivers side rear wheel compelely fell off while driving. I was doing about 30 MPH and felt like there was a flat tire so I was in the process of pulling over when the whole rear assembly snapped. The wheel hit the rear quarter of the car and bounced about 100 feet down the road. I could have been on the highway and this could have been fatal I believe. Very, Very scary. As can be seen in attached photos the issue was rust from the inside. This is very concerning since there was no way for me to know this was an issue. I could have been killed or killed someone else. I believe Toyota needs to look into this since there are other Prius' out there the same...

2012 Toyota Prius 5 with 105k miles. ABS, Brake, and Traction Control lights all illuminated while driving to work. Drove to the dealership and had their service department run a diagnosis for 200$. Their scanner reported CODE C1391, and that a new BRAKE PUMP and MASTER CYLINDER ASSEMBLY would need to be replaced for a total cost of $4,000. Toyota has a Customer Support Program Bulletin indicating that certain 2010-2015 Toyota Prius will experience internal malfunctions and require repair for BRAKE BOOSTER AND BRAKE BOOSTER PUMP ASSEMBLIES. Since this is a safety issue, Toyota should extend the program indefinite and repair their faulty systems.

Wednesday morning I went to start my car to go to work. I noticed the brake would not go down. It was difficult to press. I was unable to go to work safely. I brought my car to a mechanic where I was informed it was a faulty brake booster. When I researched online, I saw many many other Toyota owners went through the exact same issue. There is no recall but it’s a huge issue and a a safety problem.

ABS Pump and Actuator failed at 100,000 miles. Traction control, ebrake, ABS light came on while driving. Many other stories of Toyota vehicles with the same failure.

My actuator is failing. This is a known issue for Priuses and a danger to those on the road. Toyota issued a voluntary service program on these parts to avoid a recall and now many are on the road with actautors that should have been replaced.

ABS brake system doesn't work with three warning lights on and warning beeping sound. I'v learned that Brake actuator failed. Current mileage is only 67300.

ABS Break Lights turned ON and it need replacement. Toyota have faulty ABS this is my 3rd Prius that have the same Issue.

I started noticing a strange noise when I applied the brakes. It was an electronic type of almost grinding sound. When I looked into it, it was determined that the brake actuator was failing despite no warning lights coming on. This started around the beginning of March. Finally in the beginning of July the noise stopped and a lot of dashboard lights came on including ABS, BRAKE, and others. This is when the brake actuator actually failed, and the battery no longer was charged when the brakes were applied. This is extremely concerning that a major brake component can fail like this and affect the safety of the vehicle. I am attaching a photo of the dash that shows the lights that came on when this failure occurred.

In 2019, I took my Prius in for service. I reported that when I suddenly brake, the pedal feels spongy as if the brakes will not stop vehicle and lights on dash lit up. Toyota did diagnostic, no action taken by service department at Toyota dealership. I have service history documentation. On June 29, 2024 we had routine maintenance and the service department of the Toyota dealership recommended brake fluid serviced. On July 1, 2024, I was driving my child home from his summer camp and when I tried to stop the brake did not work. I started pumping the brakes several times until the car slowed and came to a stop. The lights on the dash lit up again. The brake failure put my son and I in danger. We had the car towed to the service department of the Toyota dealership. The service department sent the following information...

Completely lost vacuum brake assist without any prior warning, while driving on the interstate. Got warning lights on the dash for brake and ABS, when it happened. Fortunately there was little traffic, but if there had been even moderate traffic, it could have caused a crash. Checked the codes and found a C1391 leak in the accumulator. Dealer has quoted me $3200 to repair.

Hi NHTSA, I have a 2012 Toyota Prius and all the Brake-related lights came on the dash. ABS and TC stopped working and the Brake Pedal lost sensitivity. I was about to crash the car and immediately took my car to the Toyota Dealership. They said that there was a Recall unfortunately the program has expired on my vehicle. I asked a couple of Toyota Prius owner friends and half of them had the same issue and they have been fixed under a program. But they said my 95k miles Prius is barely out of the program. My concern is that they charged the diagnosis cost released my vehicle and said that it was not safe to drive! I don't have the budget to cover the Manufacturer's low-quality BRAKE Booster production and I have to drive my car every day! I don't want to risk anyone but I have no...

The contact owns a 2012 Toyota Prius. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed; however, the vehicle did not stop as intended. In addition, several unknown warning lights were illuminated. The contact used the parking brake to stop the vehicle. The vehicle was towed to the dealer where it was diagnosed with a failed brake master cylinder, accumulator, and brake booster. The contact was informed that the brake master cylinder, accumulator, and brake booster needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure and a case was filed. The contact was informed of an unknown recall for the failure; however, the contact was informed that the recall had expired. The failure mileage was approximately 136,000.

Traction control, brake, and abs warning lights all came on at once while driving on freeway. Braking became harder. Car has fewer than 60,000 miles. I took it to the mechanic. He says I need a new booster pump.