The brake booster and master cylinder failed on my Prius. The diagnostic code is C1391 Abnormal leakage in accumulator, which is a code covered by Toyota-??s prior recall on this vehicle.

- Palo Alto, CA, USA

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.

- Anaheim, CA, USA

Noticed a whirring/hydraulic sound that occurred every 5-10 seconds. Could only hear sound if no music was playing and not driving at highway speeds. Sound was noticeable upon parking or exiting vehicle. Only noticed sound because it occurred more frequently than usual. Spouse who is hard of hearing could not hear sound at all. My understanding of sound was that it was normal for vehicle, however, within the time span of approximately 2 weeks, sound became more frequent. Researched noise, and found it was the brake booster assembly pressurizing. Took vehicle to dealership to have it confirmed. Per dealership "Accumulator inside brake booster has internal leak causing accumulator to constantly run." Brakes did not show signs of loss of function and there was no indicator lights on dash to warn me of problem with vehicle. When I inquired with dealership of how much longer they would last, they informed me they could not say, and that it was likely they could go out at any time. Called Toyota Customer support to see if they could provide any assistance. They stated a support program had been issued back in 2021, but is now expired. According to support program 21TE01, Toyota was willing to replace brake boosters that had already failed and could be confirmed with diagnostic code. However, as the part had not failed or showed signs of failure at that time, vehicle would not have qualified, and it was prior to current ownership. Owners should not have to wait for their brakes to fail in order to recognize they have an issue. If I had not heard the noise and brought it in BEFORE an accident occurred, it could have been very dangerous indeed. Now I am left to pay $2500 out of pocket for repair of a faulty/failing brake booster assembly.

- Denham Springs, LA, USA

We were on the interstate when suddenly our cruise control stopped working. We then noticed several lights on the dashboard lit up, related to traction control, brakes, and ABS system. We could still use the car brakes, but it took more pressure than usual to engage the brakes. We pulled over to an auto parts store, but they stated there were no ODB codes logged. After researching online, I suspected a brake booster failure as described in Toyota's Customer Support Bulletin ZJB. At my earliest convenience, I brought the car in to a Toyota dealership, who confirmed that the brake booster and master cylinder were failing and needed to be replaced. Thankfully, the brakes did not fail outright, but the situation could have ended much worse. I understand by reading online that this is not an isolated incident. I encourage this issue be more thoroughly investigated so that a proper recall can be issued if needed, to bring this to the attention of other drivers of affected vehicles.

- Hutchinson, MN, USA

Code C1391 - Abnormal Leak in Accumulator. Accumulator for the brake pump is not holding pressure so the pump has to keep turning on to refill. Brake pump and ABS unit have to be replaced. In emergency situations, a malfunctioning ABS module leads to increased stopping distances and loss of steering control during hard braking. Lastly, tires can be worn more easily, which could lead to tire blowouts. This puts myself and others at risk for deadly consequences due to an increased chance for collision if I am unable to control or stop my car. This problem has been confirmed by Toyota and multiple years of Toyota vehicles have had their brake actuator assembly warranty enhanced. The warranty enhancement program has secondary coverage, which is applicable for 10 years from the first date of use, or 150,000 miles, whichever occurs first. Currently I meet the 10 year requirement but have 162,000 miles on my prius, which is completely frustrating. Many have posted with the same problem of being just outside the warranty. The vehicle has been inspected at a Toyota dealership. A symptom was noticeable starting from over 1 ? years ago when I was under 150,000 miles. The car produced clicking sounds when the brake pedal was held down at traffic lights. Once released, the clicking sound would stop. I spoke with a Toyota mechanic and he told me it was an issue with the brake pump and ABS unit, but Toyota would not repair it until it completely failed. He also mentioned that there was coverage available for the ABS unit once it failed as it was a common issue for the Toyota Prius. If Toyota warranty allowed for the brake pump and ABS unit to be replaced when the symptoms appear instead of when it completely fails, I would have qualified with my mileage. Not only is the repair costly, but for those who cannot afford it and need to continue to use their car despite the brake pump and ABS unit failure, risk their own and others safety when continuing to operate their vehicle.

- Gainesville, FL, USA

the brakes have not failed yet, but there is a known issue with the brake booster on my model year. I would like to have the government force Toyota to guarantee the brakes for a longer period of time. currently Toyota has extended the warranty out 10 years / 150k miles from date of first use. Since these cars last so long, this should be 20 years / 300k miles from date of first use.

- Lake Oswego, OR, USA

The ABS and traction control system in my 2014 Toyota Prius 4 are not functioning. They ABS light an the traction control lights are both on. I work in the automotive industry and I used a code reader to pull the codes and got a C1391 which is a brake booster and brake booster pump. That means either the brake booster has failed or the master cylinder is leaking. I contacted Gosche Toyota in Hemet and after waiting for a service writer to contact me (which they never did) I called 5 times till I finally got someone on the phone. They were very familiar with the problem. The problem is so common that SOME vehicles have been recalled. But for others like mine only a "Customer Support Program" was made. That program covers repair "if the parts are available" only for 10 years or 150,000 miles whichever comes first. But for someone like myself who has 170,000 miles Toyota says there's nothing they can do. The cost for me to repair it is $4800. The customer support program bulletin "ZJB" even says that service writers are not allowed to tell customers about the problem or the customer support program. That way when the car doesn't meet the requirements, they won't be responsible for the repairs, even though they know it will eventually fail. There is a lawsuit somewhere regarding this very same problem but for me, I'm screwed. I depend on my car to make money and now me and my family are out of a car. This is a known defect and a safety concern. Toyota is okay with leaving us with nothing.

- Winchester, CA, USA

Brakes are not woking at full specification due to brake accumilator having an internal leak C1391

- San Jacinto, CA, USA

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.

- Miami, FL, USA

Good Evening, I'm writing to request a callback in regards to my 2014 Toyota Prius which is subject to a recall. "The involved vehicles were designed to enter a failsafe driving mode in response to certain hybrid system faults. Toyota has found that in rare situations, the vehicle may not enter a failsafe driving mode as intended. If this occurs, the vehicle could lose power and stall. While power steering and braking would remain operational, a vehicle stall while driving at higher speeds could increase the risk of a crash." I recently just moved back to South Florida, I was living in NJ for a few years and had the Inverter malfunction earlier this February, 2023, forcing the car to enter the fail safe mode described giving me the warning to "Check Hybrid System, Stop the Vehicle in a Safe Place". The car was at Toyota Universe, Little Falls, NJ for about 45 days, since this was going to take the complete replacing of the inverter and an update of some sort of software. After receiving the car back around March 17th, I moved back to Florida about 2 weeks later. This evening around 5:30 returning from work, the car stalled again while I was driving surrounded by dense traffic, wouldn't accelerate with all lights flashing. Thankfully I was able to pull over slowly into a parking lot after which my steering wheel locked, and my car was no longer able to be put into Drive or Reverse. Car was only able to shift into Neutral and Park. This was the most terrifying experience of my life had something worse happen in the middle of traffic. I have dropped off my car to the dealership parking lot and will be checking it in first thing in the morning. I'd like to ascertain what I should expect from Toyota Manufacturing should this issue be unfixable? I am more than happy to let them attempt fixing it, but I also need to live a normal life and don't feel the need to be responsible for a manufacturing defect putting my life in jeopardy every time I go drive.

- Pembroke Pines , FL, USA

Was at Toyota dealership looking at 2023 Prius and 2023 Corolla Cross for daughter. I decided to leave and when I started backing up, my daughter noticed the Brake, ABS and Anti-Skid lights all came on at once. She asked if that was normal. It was not. A few minutes later, they stated flashing, then went out after I turned the car off. I live over an hour away and decided to drive it to Walmart, which is approximately 2 miles from the dealership and upon getting into the Walmart parking lot the lights started flashing again and upon applying the brakes, we heard a loud grinding sound. We didn-??t think we were going to be able to stop! I immediately parked it and called my husband to tell him our horror story and to come pick us up. Our prayers were answered when he came and we were able to drive it slowly to the dealer. It was a cold rainy night to be on the road with braking issues. This is a very dangerous if not deadly situation! Shame on Toyota for not recalling this. How many lives have to be lost before you take ownership of your faulty hybrid braking system. We demand this be fixed for free regardless of mileage and be made a recall-??NOT A CUSTOMER SUPPORT PROGRAM. RIDICULOUS!!! I don-??t think our daughter wants a Toyota hybrid anymore-??

- Rocky Mount , NC, USA

I was in stop and go traffic. We got into a crash and my vehicle was totalled. I-??ve never been in an accident before. It felt like the break system just broke down.

- Harlingen, TX, USA

2014 Toyota Prius. Consumer writes in regard to hissing sound coming from brakes.

- Marietta, GA, USA

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.

- Clarksville, TN, USA

Aloha! I got 3 lights lid up on a dashboard: traction control, abs and brakes. C1391 error is coming up on obd reader. I researched online and found that it-??s a common issue, brake booster and actuator needs to be replaced. Many people having same problem. I found your website because of this YouTube video where many people found same problem: https://youtu.be/xA9jyrbZDWo

- Kailua Kona , HI, USA

BRAKE BOASTER FAILURE. Dashboard lights illuminated: Brake, ABS and Traction. Brakes themselves felt spongy. Car felt very unsafe. I did find out that Toyota has a hidden Customer Support Program ZJB. However, the dealer found my diagnostic code to be c1202 and the Customer Support Program ZJB only supports repairs for codes c1391, c1252, c1256 or c1253. However, the exact same symptoms and safety issues were experienced and all the exact same warning lights also came on. The dealer-??s diagnostics resulted in a $2,087 replacement of the brake booster.? The dealer did contact the Toyota district manager along the way.? He denied coverage based on the diagnostic codes reported BUT again I am arguing that my crazy expensive repair had the EXACT same symptoms, safety issues, and repair (e.g, brake booster replacement). The car clearly could not be driven. Note my Prius only has 92K miles.? Attached is a picture of the dashboard warning lights that came on and the dealer invoice for the repair.?

- Newport, RI, USA

Brake being less effective to be spongy and keep losing pressure. The brake actuator constantly making boosting noise. Making driving unsure that the brake working even no warning light on yet.

- Sarasota , FL, USA

On August 28,2020 we were driving in heavy rain for 1 1/2 hrs to fayetteville. Our brake ABS and engine light came on. We assumed the lights would go off, when we did not drive it doing the night, but next morning it came back on. We carried to mechanic shop today Sept. 1, 2020. They could not read any errors and said need to carry in to a Toyota dealer. We have not set up apt. Just left vm. Hopefully they will call us back today

- Katy, TX, USA

The Prius vehicles covered only by warranty enhancement zjb are suffering the same dangers from brake booster pump failures as those Toyota covered safety recalls D0H and K0L. By excluding Prius with defective brakes from D0H and K0L, Toyota has left the owners to helplessly experience life-threatening brake failures or malfunctions before Toyota will provide the replacement brake components needed to make the car safe. The law requires Toyota to prevent the life-threatening dangers of this defect before brake failure occurs. Toyota's cost-cutting strategy is causing crashes. Injuries and crashes caused by the brake defect explained herein have been reported to NHTSA. Toyota's decision to provide post-failure repair reimbursement - instead of a preventative safety recall remedy - explains many of the crashes and injuries reported to NHTSA. Here is a list of relevant complaints from safercar.gov: 10794873,10875685,10876015,10927047,11231660,11219354,11014878,11151142,10680404,10627821,11154835,10983408,10704553,10734278,11173353,11064519,10971881,11186947,10923921,10573591,11243249,10819439,10592400,10919990, 10851950,10855586,11240240,11197067,11193820,11173721,11156466,11144698, 11235210,10550179,11253950,11102264,11044156,11253725,10616134,10875625, 11231596,10584723,11207636,10749388,11014797,11203834,11203591,11193354, 11182610,11155778,11130742,11129946,11164336,10498096,11219901,11154783, 10598545,11228248,10547701,11110691,11164990,11222966,11207630,11192342, 11184751,11183661,11183178,11173804,11173173,11173044,11162242,11144888, 11139660,11121916,11088447,11080403,11061959,10984549,11073636, 11034572, 10870866,10929397,11104163 when the brake booster pump assembly fails in a Prius vehicle excluded from D0H, C1256, C1253, C1252, C1391, U0293, and other dtcs indicating dangers and FMVSS noncompliance are being stored.

- San Juan Capistrano, CA, USA

When I start the car and it becomes idle the brake pedal becomes stiff and gets stuck. I have to put the car back in park and restart it for the brake to work properly. This doesn't happen all the time but happens enough for me to be concerned. I took it to two Toyota dealers and they couldn't duplicate it and couldn't find a problem but it is still happening. This only happens when I start car not while driving.

- Chicago, IL, USA