2014 Toyota Prius

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.

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.

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 ½ 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.

I was dropping my daughter off at school and the car completely shut down on me and turned off in the middle of an intersection. I have just had brakes and oil changed but ever since I got the car codes keep popping up and when checked it’s all good. Front lights keep glitching and even with new brakes there is still a bad sound. My dash computer thing keeps going in and out. It happens a lot more when it rains and makes a sizzling sound I’m afraid to drive it in the rain. I’m besides myself how the car turned off on me and my child we couldn’t move I could accelerate and we almost got hit then another light came on and I couldn’t even turn my wheel. Very dangerous

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.

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.

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.

The contact owns a 2014 Toyota Prius. The contact stated was unable to start the vehicle. Additionally, the hybrid system warning light was illuminated. The vehicle was not drivable. The contact towed the vehicle to the local dealer, where it was diagnosed with needing the inverter assembly to be replaced. The vehicle was not repaired. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V369000 (Hybrid Propulsion System). The manufacturer was informed of the failure and the contact was informed that the recall repair had been performed on August 20, 2020. The failure mileage was approximately 86,500.