The brake booster system suddenly failed in my 2013 Prius. I was driving when the ABS warning light, the brake warning light, and slip indicator light came on. The brakes became soft and it was difficult to stop the vehicle. I had it towed to a local, independent mechanic and the entire brake assembly had to be replaced. Toyota offered an extended warranty for this repair that expired in August of 2023, admitting that their vehicles contained faulty parts. This is absolutely a major safety issue that should be covered by Toyota regardless of when it manifests.

- South Carolina, SC, USA

As I was driving, the ABS, Brake, and Traction Control lights all illuminated on my dashboard and have remained on since. I took the car into the dealership to get a diagnosis, and they told me that I had a accumulator leak and needed to repair my brake master cylinder and replace the brake booster pump assembly. This is apparently a known issue with Toyota Prius, as hundreds of others have discussed this in various forums.

- San Francisco, CA, USA

I am the joint title owner of a 2013 Prius. This complaint is Case # [XXX] at Toyota. Our [XXX] daughter has full-time use & possession of this vehicle. In her own words, this is what happened: -??I was driving on the [XXX], about to merge onto the [XXX] in Los Angeles. This is an extremely traffic-heavy interchange. Approaching the stopped car in front of me, I applied my brakes. The brakes did not work properly. I had to press the brake pedal much harder than I normally do, & my car kept going for another two seconds or so before stopping. Three dash lights came on -?" ABS light, brake light, & light with the swerving car symbol. There was a -??puffing-?? type of sound from the brake pedal that lasted about a second, then stopped for about two seconds, then started again, & so on. That sound would come out of the pedal area regardless of whether I applied the brakes. Frightened by the brake failure, I pulled off the freeway in downtown L.A. I turned the car off & let it sit for a few minutes. When I turned it back on, the same three dash lights came back on, & the car was still not braking properly -?" still the delay, the need to press harder than usual, & the sound. I drove directly to my Toyota dealer. It was a 35-minute, nerve-wracking trip.-?? The dealer found "CODE C1391 ABNORMAL LEAK IN ACCUMULATOR." Cost of repair was $3,163.12. Note also that in 7/23, she had taken the car to the dealer with the "SAME sound" (her words) when braking. The dealer could not duplicate the problem. They did not conduct a brake test at that time. Online, I discovered that this serious safety issue had been raised in a previous petition, investigation, & customer support program that expired. This problem is the subject of a CURRENT, OPEN, NHTSA Action, # DP23005. Toyota knew of this problem, instituted a program due to safety risks from C1391, allowed the program to expire, & has left us at risk without warning. Our other daughter owns a 2014 Prius. This needs recall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOI

- Altadena, CA, USA

ABS Brake Warning Light On-stays on-this just happened within last 2 weeks. Not sure on safety measures but unsure if I keep driving it the brakes will just give out. The problem has been confirmed and seen by Tire Max but no diagnostic tests were ran. The just saw the light was on. No one has inspected the vehicle component by the manufacturer, police, or insurance company. No warning lamps prior to the problem but the ABC Warning light stays on while cranked and it first appeared about 2 weeks ago. I do want to add that a similiar recall or warranty had been put out by Toyota on Sept 4th 2020-(T-SB-0089-20) for 2012-2014 Prius V & C stating: "Some 2012-2014 model year Prius V hybrid vehicles may exhibit a condition where the brake, ABS, and/or TRAC warning lights are on and/or a Check VSC message displays. Diagnostic Trouble Codes (DTCS) C1391, C1252, C1256, C1253 may be stored. This condition may be caused by a small internal brake fluid leak inside the brake booster assembly with master cylinder. The warranty was for Prius V or C but my Prius(no V or C) has been affected with the same issue but Toyota will not honor this warranty or recall due to the problem not showing as specific to my vin#. So I am reporting this problem so it can be submitted that there is a similar problem with my Prius as well as the Prius V or C so others could submit their problem as well. I cannot afford to fix this myself. I need Toyota to back up their cars.

- Eden, NC, USA

ABS, brake. Anti lock lights

- El Cerrito, CA, USA

I was driving home on a busy street in Houston, TX on a clear day. I tried to slow down due to traffic & the following warning lights appeared on the dash: red brake system warning and yellow brake light, ABS, brake system warning light & the slip indicator light. Right after, I came to a red light & started to brake, the car felt like it was on ice and couldn't stop properly. Fortunately I didn't have to come to a complete stop because there were many cars in front of me and the light turned green. when I stopped applying pressure to the brakes the car sort of shook side to side. Each time I had to brake, the car felt like it was on ice, I had to put the hazards on & give myself a very large amount of room to stop the car. While at a red light I turned the car off/on; no change in the dashboard lights. I turned onto a street w/ less traffic; pulled over, turned the car on/off again and no change. I was less than a mile from home so I drove the rest of the way w/ my hazards on & never went faster than about 15 mph; even at that speed the car took too long to come to a complete stop, it felt like I almost had no brakes at all. Thank God I wasn't on the highway w/ no brakes!! This is a HUGE safety issue, someone could die or be seriously injured. Had the car towed to a Toyota dealership on Mon 1/15/24; they said there was a brake fluid leak in the master cylinder & malfunction of brake booster pumps, the code was C1391; both parts needed to be replaced. Total cost for repairs $3800. Had the car towed to a mechanic, paid $2600 for the same service. Per my research this is a known problem with this generation of Prius', Toyota offered an "enhanced warranty" to replace the parts if they were broken, but the dealer said my warranty expired in 2022. Why weren't owners made aware of this issue and warranty? I would have brought the car in for repair in the past if I knew there was a defect with the car. The car should be recalled.

- Houston, TX, USA

ABS, Brake, Trac warning, and brake lights turned on. When I used a diagnostic device, I read the code C1391 code. The brakes of the vehicle are not working properly. Upon my research, I found that several factors can trigger the C1391 code, including a faulty brake accumulator pressure sensor, low brake fluid level, brake system leaks, issues with the ABS pump/motor, or electrical problems within the brake system. This problem has many safety implications. The brake system is fundamental for vehicle control and stopping power. Any compromise in its performance poses a risk to the driver, passengers, and others on the road. Prompt action is necessary to investigate and rectify the root cause of the C1391 code to ensure the continued safety of affected vehicles. I think Toyota company should issue a recall for this faulty system.

- Lakewood Ranch, FL, USA

While driving on the freeway, all of a sudden the ABS, Slip Indicator, Brake, and Brake System lights lit up on the dashboard. I immediately switched lanes to one that had no cars in front/back of me since I was going about 55mph. I tested the brakes since I saw the brake lights appear. It felt as though when the brake pedal was pushed, they didn't activate until you reached a certain point, almost to the point where the pedal needed to be fully pressed to stop. It didn't feel like the brakes were fully functional and behaving in the way they were prior to the lights appearing. I was afraid the brakes would give out. Then I noticed a whirling/hissing sound that was consistent. The sound was easier to hear when the car was at a complete stop but it could still be heard while driving. We took the car to a local Toyota dealership/service dept to get it evaluated. They diagnosed the car saying it needs immediate attention and is not safe for driving since it involves the brakes. The repair invoice stated VARIOUS BRAKE WARNING LIGHTS ON C1391.

- Kailua, HI, USA

ABS, Brake, and Traction control lights are on alongside a constant beeping. I have lost regenerative braking and it now takes more effort upon the brake pedal to come to a complete stop. I am in fear that the brake system will go out completely, causing damage to myself or my children.

- Zephyrhills, FL, USA

Brake pump failed while on the highway. Brake functionality and braking distance changed drastically while driving high speeds. Dealer confirmed that the breaker pump and master cylinder must be replaced with a new assemblies. There was no recall for this failure, but a Toyota Customer Support Program for replacement of this brake assembly was active for reports of this failure only before April 2023. Toyota dealerships are not obligated to cover this replacement or make customer aware on any suspected vehicle unless the failure was present before April 2023. Warning lamps only appeared at brake pump failure - not before failure.

- Jersey City, NJ, USA

BRAKE BOOSTER AND BRAKE BOOSTER PUMP ASSEMBLIES. making a buzzing noise. cost to repair is estimated to be 2500 or more. Toyota even has a bulletin for it, but they did not inform the public, because the part is very expensive and difficult to fix on a prius. since it has expired, we are out of luck.

- Hacienda Heights , CA, USA

The brake accumulator and brake actuator failed while driving and lost brakes. I had to step on the pedal very hard to avoid a collision. Check engine light C1391 came

- Temecula, CA, USA

Brake system failure. Traction control light, brake light, abs light, and brake system warning light all lit up on dash. The regenerative braking is no longer working or charging battery. Obvious loss of stopping power. Does not feel safe to drive at all. Toyota wants $3,000-$4,000 for the repair. Toyota should be held liable for these failures causing crashes and potential fatalities. This should already be a recall.

- Atmore, AL, USA

Factual Background: I purchased the vehicle on May 2, 2023, with approximately 61,000 miles on the odometer. On October 22, 2023, the vehicle displayed Diagnostic Trouble Code (DTC) 1391, which is a known issue with Toyota Prius vehicles. Currently my vehicle currently has approximately 86,000 miles on the odometer. I first contacted Toyota on October 27, 2023, and spoke to Tier 1, Tier 2, and ultimately to a Tier 3 support representative. I was told that I could not escalate further, but that a supervisor would do a one business day call back. On October 30, 2023, I received a call back from a supervisor who escalated my case to the Executive Office. On October 31, 2023, I received a call from the Executive Office and asked for their address in order to file a formal complaint. On that very same day, I went to Peterson Toyota to have them confirm DTC 1391, which they did and my visit and paperwork is recorded within your internal system via Toyota Information System (1TIS) per the dealership. I am requesting that Toyota fix the known and now verified defective brake booster and brake booster pump in my vehicle at no cost to me, the consumer, pursuant to the Magnuson-Moss Warranty Act and implied warranty of Toyota-??s products. Again all of the details regarding my vehicle and its history are found on Toyota Information System (TIS). There have been several complaints about this known issue and an investigation needs to be reopened regarding this ongoing issue. Several class action lawsuits are getting settled before consumers have a chance to hold Toyota liable. Will someone from the NHTSA please start an investigation or facilitate in any way to get an investigation into to this reoccurring issue. Brakes matter and society is depending on government and corporations to be transparent and ethical. The FTC, BBB and Attorney General-??s need to act on behalf of everyone in keeping our roads safe and holding Toyota accountable again. Too many people-??s lives matter.

- Kuna, ID, USA

What component or system failed or malfunctioned, and is it available for inspection upon request" Brake Booster and Brake Booster Pump Assembly have failed. Part are available for inspection. How was your safety or the safety of others put at risk? Had trouble stopping on the highway and at intersections. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear" No. Problem happened before warning lights appeared. Later, problem was verified with error codes, dash lights, and sensation of brake action.

- Austin, TX, USA

Brake booster defect caused ABS and brake light went on, thus we lost ABS while driving. Initially we heard noises while breaking in April 2023, told to change break pads. We went in to Toyota dealer again in Oct 2023, and diagnosed with brake booster problem, leaking gas inside. Toyota knew that its brake booster has a defect in design and has customer support program as a post failure solution vs recalls as a preventative measure. We were never informed about this customer support program regarding defect in brake booster. Toyota declined to repair saying my car already missed the time window (10 years since first use). Toyota should recall brake booster assemblies for Prius 2010-2015. In my case, due to delay in diagnosing this serious problem, I was put on a serious financial burden to pay for this repair ($2800 quoted by Toyota dealer). I was also put on a life threatening risk of driving a malfunctioning car for a long time without being informed. Since the beginning of this incidence, I-??ve called Toyota four times and Toyota acknowledged that they did not inform me and Toyota dealer failed to make a proper diagnosis on time to repair.

- San Marino, CA, USA

To whom may be concerned, The car I own is Toyota Prius 2013, it has the brake issue nearly a year: I can hear the brake booster pump works every 8 seconds, and the worse thing is the car is jump and has a longer brake distance when I step on the brake paddle. I even nearly had a incident at the intersection because the brake lag. I know Toyota has customer support program ZJB, and I also brought my car to Toyota Dealer. But they say they can replicate the issue. But according to the program, it must be some light on to be qualified. So now I have to take care of over $3000 bill by myself, otherwise I have to take a risk to drive my car with the brake issue. I searched online, there are a lot of customers have the similar issues like me. So Toyota has already known this issue, but why they just still wanna those cars running on the road, brake system is the most important part, it's Disregarding human life. Thanks for your time. Best Regards [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Fontana, CA, USA

The brake actuator keeps buzzing every 3 seconds or so the entire time the car is on and even after I turn the car off and get out. The brakes make a wierd burping noise and the pedal depresses with each noise if I am stopped at a red light or stop sign with my foot on the brakes. All of the brake, abs, and traction control lights lit up. The regenerative braking is no longer working.

- Longview, TX, USA

I was driving around 65 miles per hour on the highway, when I suddenly feel my brake were not working properly. Brake light, abs and traction light were shown at the same time. I almost felt like it was kind of break failure. Break would only work if i push all the way to the floor.

- Grand Prairie, TX, USA

When the car was being driven on a surface road, the ABS, Brake and Traction lights came on. The brakes became stiff and hard to press. Braking was also slow. Car was traveling at less than 30 mph at that time When taken to the mechanic shop, and running diagnosis, the code came back to be C1391. The car has 113000 miles and purchased in July 2013.

- San Jose, CA, USA