Got code C1391, a common issue with the Prius. Brake Booster Assembly is defective due in no part to owner/driver of vehicle. This creates a serious safety issue with braking. Traction control light, brake light, and ABC light are all on and repair is ridiculously expensive.

- Nashville, TN, USA

Apparently there is a known defect on the brake actuator/master cylinder/booster on the 2014 Prius that would have been addressed if the car had been driven for less than 10 years or 150,000 miles. We purchased our car in April 2014 and the part just failed yesterday at only 126,000 miles. We understand that there is a pending class action suit (or perhaps one that was settled) but do not know how to become a member of it. It seems as if they knew that the part was defective, but did not offer to do a voluntary recall and remediate this before a failure, they should have, but instead, now we have a $3400 repair bill. Requesting assistance in evaluating whether there was negligence and or liability for them not addressing this issue in a timely manner.

- Jacksonville, FL, USA

Yesterday, while driving on the interstate, all of the brake related warning lights on my dashboard lit up- ABS, traction control, brake, caution)- causing me concern, so I looked for the next exit. While exiting and slowing, I noticed my brakes felt different and were not as responsive as usual. I called my mechanic and cautiously headed to his shop a couple of miles away. Today, I met with him and found out that there is a leak in the brake booster line, but the extent of the problem is yet to be determined. I immediately did an internet search for my model year and found that there was a safety campaign on other Toyota hybrids for that year, so I called the Toyota customer service number. I was told that my vehicle had an extended warranty for the brake booster, but it expired 9 months prior, 10 years post purchase, The rep has escalated my issue but I will have to wait to see if someone with more authority can potentially give me an additional extension. Meanwhile, my car is not drivable, as the brakes could fail at any moment. In my estimation, this should not be a time limited coverage, but an actual recall covered by Toyota. This is not normal brake pad rotor wear and tear, but a known issue with the assembly system and a true safety hazard that one cannot foresee without experiencing minor to catastrophic failure of the system.

- Penitas, TX, USA

The brake master cylinder and brake booster failed. It is available for inspection upon request. My safety was put at risk as braking distance increased significantly. The problem has not yet been confirmed by a dealer or independent service center. The vehicle has not yet been inspected. The warning lights appeared upon failure. Brake warning light, traction control light, and ABS light appeared. Prior to complete failure, the brake booster would cycle on after opening the door and would then cycle every few seconds for 10 minutes or so after parking.

- Chino Hills, CA, USA

Something felt wrong with the brakes for many years, but mechanics checked the brake pads and rotors and said they were fine on multiple service visits. I had multiple close calls during quick stops on highways, I though I just needed new tires. I then started to hear a whirring buzz noise become more and more frequent. I researched what it was and found on reddit that there was customer support program ZJB to repair failed brake accumulators, which affects hundreds of thousands of these cars. The problem was that my brakes were only in the process of failing rather than being fully failed enough to send codes and light up the dashboard, which is the only way the customer support program would cover the $4,000 repair. The failure finally happened when I was three hours from home and had half the braking power as usual and had to limp the car home for fear of the brakes going completely out. I can't believe Toyota is letting this many people drive around with a potentially catastrophic brake issue.

- Philadelphia, PA, USA

I was driving on the highway during rush hour when a loud beeping noice began. My 15 year old cousin was in the passenger seat and began to check for the source of the beeping. I was driving 55mph on a busy highway with no safe shoulder stop. As I was preparing for the exit, the brakes suddenly became dysfunctional. The pedal was extremely hard to press down and I found myself unable to slow down the car in enough time to avoid hitting upcoming traffic. I found myself in an urgent, life threatening situation and needed to pull over into the emergency lane located before the exit. I could not just consider my safety, but that of other drivers and my 15 year old passenger. She is traumatized. I was able to get the car to stop with my entire weight on the pedal. Once stopped, I scrambled to find the reason for the sudden brake problem, checking if anything rolled under my foot, if the floor mat was loose, if the gear shift was wrong, even checked if I accidentally hit the emergency brake. Nothing was out of place. No new dash lights. I looked in the manual. I had no information. I went to jiffy lube and they performed a diagnostic test and informed me they are unable see all the codes with hybrids because Toyota-??s computer can only see Just in August I went to Toyota for my oil change, nothing was said about the brakes needing to be fixed and how repairing them now would prevent the failure of the accumulator pump system. If I had known paying $400-$500 for the brakes then would prevent having to pay $3000 to replace a pump. I would have made that sacrifice and went outside of my budget. This is paramount information that should be disclosed to all Toyota customers that take their car in for care and pay. After further research, I STRONGLY BELIEVE TOYOTA EMPLOYEES PURPOSELY WITHHOLD INFORMATION FROM THEIR CUSTOMERS NOT INFORMING CONSUMERS ABOUT AVOIDING PUMP FAILURE AND THE NEED REPAIR THEIR BRAKES AND IS COMPLICIT IN ANY INCIDENT CAUSED BY PUMP FAILURE MAY CAUSE.

- Savannah, GA, USA

Without warning, my brakes completely stopped working and I was fortunate enough to be somewhere I was able to pull over without being killed. Toyota is aware of this issue, but put a 10 year timeline on the complementary repair, which is totally unacceptable, as owners were not notified directly about this program, therefore how could we know it existed, was a problem, and to go get it fixed within their arbitrary deadline? I could have died losing brakes on the freeway, or even could have killed or injured others. This is a known, and severe safety hazard, and Toyota is not taking responsibility. It is unconscionable. Hoping for a class action lawsuit. It was a $5500 repair in California, which was almost the value of the car. Absolutely brutal and horrendous business practices from this company. Shame on them. I hope this agency NHTSA will add this report to the pile of others who have reported this, and actually take meaningful action for those of us who have been put at risk, and ripped off in the process.

- Los Angeles, CA, USA

My 2014 prius experienced a failing brake booster actuator assembly. I was driving when suddenly my traction control light came on and my brake pedal turned mushy. I pulled over to a parking lot and put my vehicle in park. As soon as I did this, the ABS and parking brake light both turned on. I had the vehicle towed to the Toyota dealership. They diagnosed the problem as an internal leak in the brake booster actuator assembly. This is a common problem with these vehicles, but instead of Toyota issuing a recall, they only did an extended warranty coverage of which my prius didn't fit the parameters. Now I am stuck with a vehicle that is unsafe to drive and a repair estimate of $3,900 because of one of their parts failing. This should clearly have been made a recall with the volume of prius owners experiencing this problem. What a disappointment after having 3 Toyotas for many years.

- Anaheim, CA, USA

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

- Mount Dora , FL, USA

The braking system is failing with the following codes I tested with the BlueDriver scanner. Code TypeCodeDescription ABS CodesC1241Low or high power supply coltage ABS CodesC1391Abnormal leak in accumulator Main BodyB1206P/W Master SW ECU Communication Stop Main BodyB2321D-Door Motor ECU Communication Stop Main BodyB2430LED Headlight LH Entry and StartU0142Mainbody Ecu Communication Circuit Entry and StartU0155Lost Communication with Instrument Panel Cluster Control Module The car is available for inspection. This puts the drivers, myself and fiance, at risk of catastrophic collision in the event that the brakes fail while driving. I will call Toyota to obtain a replacement of the system that has occurred with many other drivers. The vehicle has not been inspected by manufacturer yet but it is important to know that this is a serious problem that could kill people. The problem was identified when warning lights came up on the dashboard but there is also a sound coming from the brake actuator that shows a problem. The problem is due to manufacturer error, I have driven the vehicle normally.

- Homestead, FL, USA

So my wife is pulling into our driveway with my little ones and notices the ABS, traction control and Brake light come on. I then had the vehicle looked at by a local Toyota dealership and they tell me I'm getting code C1391 and that it's a known issue. They then tell me I'm out of my extended customer support warranty time frame and I will have to pay. According to NHTSA this is a known defect on this vehicle and it affects more than 100k Toyota Prius vehicles. So basically, we've been driving around in a vehicle that the brakes may fail at any moment and potentially kill us all but is only addressed by the manufacturer when the known failure occurs. Even then, they only address it if the error occurs during their set time frame. It seems this has been brought to NHTSA's attention on a few occasions and nothing has been done. I would think brakes are something that warrants a recall on a known defect. Thankfully my wife and kids weren't doing 70mph down the highway when the brakes all of the sudden stopped working.

- San Antonio, TX, USA

This vehicle lost braking assist while in motion on a well known problem from TOYOTA. There has been class action lawsuits on this very fact. Toyota issued a customer service warranty for vehicles that have less than 150,000 and filed before March 2024! My car has 127k and failure was Sept 9 out of the warranty. I understand that there is a line if the sand however this needs to be a recall as it effects so many vehicles and it is dangerous! I am asking you urge them to make a recall for this! I have paid for this repair and am furious but I had to do it!

- Mount Holly, NC, USA

ABS actuator failed in April of 2023 after more than a year of constant whirling, which my mechanic didn't diagnose until after my dashboard lit up with errors. The issue was diagnosed by AAA mechanics after the dashboard warning lights lit up, with a $4,000 cost to repair. Brakes are spongy, car is rarely driven at this time. We were told that the brakes would continue to work, but the ABS system would not. Now the vehicle beeps constantly when driving, which appears to mean the brakes could fully fail at any time. Based on subsequent research, Toyota was quietly fixing the ABS acuator issue until last year, but it was not offered when my vehicle was brought in last year during another recall. When it failed the car was under 10 years and 150K.

- Clearwater, FL, USA

My car started exhibiting signs of a known brake booster/brake systems failure for Priuses in the 2010-2015 range. These include the ABS, brake system, and skid/traction lights coming on and a 3-5 cycling whirring noise. The brake sensitivity is also altered. This happened suddenly today. I checked the battery voltage (normal), so this is not causing the issue. After investigating online, I have discovered that many consumers have experienced the same issue and are being denied a recall/repair coverage by Toyota. Today, I am reaching out to Toyota to see if the replacement/repair, which should be in the range of $3-4k will be covered by Toyota. According to numerous other Prius owners online, this issue is being denied by Toyota for coverage, even though it is something they are fully aware of. This is unacceptable and dangerous on their part. My vehicle has 110k miles, was leased used last year, and has not had any issues otherwise. I am up to date with all routine maintenance, including getting my pads replaced and rotors maintained last year as well as new tires.

- Lexington, KY, USA

Brake warning lights illuminated and loud beeping for the first time. Took the car to local repair shop who advised me to take it to the dealership. Dealership indicates that R&R Brake Booster assembly with master cylinder and brake booster pump assembly need to be replaced at over $3100 and brakes are at risk of failure. I researched and found the NHTSA Customer Support Bulletin - [XXX] indicating this known issue. The support period expired in March and mileage has now exceeded the limit for support. Though I have had the car in the dealership for service many times, this was never brought to my attention. The dealership advised me to contact Toyota. Toyota then advised me to contact NHTSA about the problem. Further research indicates ongoing problems with this issue that have not been resolved - [XXX] should have issued a recall for this important safety issue. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Dacula, GA, USA

Brake Booster Assembly in my 2014 Toyota Prius began cycling more often than usual in December 2023. By March 2024 it began cycling approximately every 30 seconds. Randomly while stopped or parked, there would be four warning lights illuminated on the dash - SLIP indicator, both Brake System Warning Lights - the word "Brake" and the "((!))", and ABS Warning Light. By June 2024, I would also randomly lose stopping power & a great distance was necessary to stop the vehicle. I took the Prius into my local Toyota Service Center where it was recommended both the Brake Booster Pump and Brake Booster Actuator be replaced. When I brought up Toyota's Customer Support Program for which my Prius is eligible in terms of age, mileage, and symptoms, I was told a DTC is required to verify the issue. According to this local Toyota dealership, the Master Tech confirming the issue and recommending replacement is not sufficient. Since the lights were illuminated, I asked why there was no stored DTC. They responded "Well, I'm not sure" and continued to reference the required DTC. This brake assembly is an issue that Toyota has acknowledged, but fails to accept full responsibility by issuing a recall. This gross negligence by a vehicle manufacturer.

- Kingsport, TN, USA

I lost the brakes. The Brake actuator failed. I was able to swerve around traffic to avoid a collision and get the car towed home. No warning lamps until it failed. The brake actuator was replaced and I saved the old, defective component.

- Anaheim, CA, USA

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