Code C1391 200k miles All the warning signs for brake booster issue came up. The cost is too high and I just missed the Customer Support Program timelines because the code came up late. This needs to be a RECALL, based on how many people experience this issue consistently.
2015 Toyota Prius brakes complaints
Page 2 of 4: complaints 11 to 40 of 94, newest first, as owners wrote them.
I was driving my 2015 prius for years and occasionally the brake, abs and traction light would come on this is a sign of a failing Brake actuator and booster. Toyota and the Ntsb ordered the following warranty enhancement My Brake Booster had been exhibiting signs of failing for years and I tried to get a toyota dealership to replace and repair the parts under the warranty extension but I was told I had to wait until I had perminent dash lights and trouble codes. So I had to wait till the booster completely failed. By that time my car had exited the extended warranty perimeters and I am told it is no longer eligible.... even though the components are faulty from the factory and exhibited signs of failure many years prior. I was told to wait until the compenent failed by multiple dealers. My car was in motion and the brake boosters failed, fortunatly it did not cause an accident but this is a serious safety issue. Toyota should have done a compleat recall of the brake actuator and booster pump, rather than have drivers use known faulty components until failure. Toyota corporate has refused to help in the repair of the vehicle despite it showing failure for years.
Toyota Prius has a known problem with the brake actuator and booster. A notice was sent out in 2019 under the Customer Support Program Expansion with repairs up to 10 years or 150k miles. This is a safety issue and should be covered under a recall with NO TIME OR MILEAGE LIMITS since these problems are not showing up until after 10 years if the car has low mileage, as in our case. We just passed the 10 year mark, but only has 114k miles. No mention of repairs needed were made during regular maintenance visits with Toyota. Additionally, preventative repairs were not offered if the vehicle did not seem to be experiencing problems at that time. The brakes are spongy and unresponsive. The ABS light , traction warning lights, and parking brake lights are staying on.
ABS braking system suddenly not working. ABS, BRAKE, and traction control lights all turned on.
On 4/16/26, while driving my 2015 Toyota Prius (approximately 87,000 miles) on the freeway, I applied the brakes while transitioning from the [XXX] onto the [XXX] . As I veered right on the curved onramp, the brakes failed to engage properly, causing the vehicle to spin out of control and collide with the side railing. There were fortunately no nearby vehicles on the 2-lane onramp at the time. Under slightly different circumstances, this incident could easily have resulted in serious injury or death to myself and/or others. No airbags deployed. Although I was physically unharmed, I was extremely shaken by the incident. Immediately after the collision, the brake warning light, ABS warning light, and another warning indicator illuminated on the dashboard. Prior to the incident, I had not experienced braking problems severe enough to suggest imminent failure. On 4/17/26, I brought the vehicle to Toyota of Cerritos for diagnostic evaluation. I was informed that the brake booster was the issue and that the vehicle was unsafe to drive. The vehicle was towed to a collision repair center affiliated with my insurance company. After repairing the external collision damage, the collision center informed me that the brake booster malfunction that caused the incident could not be repaired there and would require dealership service. External repair alone: $3706, in addition to increased automobile insurance premiums expected over the next 3 years. I also contacted Toyota Motor Corporation regarding Customer Support Program coverage related to brake booster issues and was informed that the program expired in 2025 and no assistance would be provided. I am submitting this report because this brake booster malfunction created a serious and unexpected safety hazard resulting in loss of vehicle control on a freeway interchange. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
My brake actuator and brake booster are failing. All of my dashboard lights have come on (brake, ABS, Traction Control, brake system warning light). Unfortunately, I am over 10 years and Toyota is saying that I need to pay out of pocket for the repairs. This is a known problem and should be covered. I was unaware of the known issue and my car didn't start having problems until after the 10 year mark. I am under 150,000 miles.
Brake Booster and ABS, Brake Master Cylinder went out in car without any lights or warning while driving the vehicle at a moderate speed on Freeway. I was able to avoid an accident and take the car to a repair shop in which at 119K miles and just at 10.5 yrs old the entire brake system had to be replaced/repaired.
In June 2025, while driving on the highway, the vehicle suddenly displayed multiple brake warning lights and warning messages, including the red brake warning light, ABS light, brake system warning light, and traction/slip indicator. At the same time, the brake pedal became stiff and braking effort increased suddenly, creating a near-crash situation because the vehicle did not slow normally. Before that incident, the vehicle had already been making abnormal brake-related noises, including a humming/pumping noise when the brake pedal was applied, and there were intermittent episodes where braking felt abnormal. In June 2025, the vehicle was taken to a Toyota dealership during Toyota’s brake booster support program period. The dealership documented customer complaints of “humming noise in cabin when holding foot on the brakes,” a request to “scan for codes for ZJB enhancement,” and that the “vehicle hard to accelerate and brakes got stiff,” but stated that no qualifying ABS codes were present at that time. In March 2026, the same condition returned and worsened. The vehicle again displayed the red brake warning light, ABS light, brake system warning light, and traction/slip light, and braking performance was reduced. An OBD scan of the ABS control unit showed code C1391, which is associated with brake booster / ABS actuator failure. The Toyota dealership has now diagnosed the vehicle with ABS actuator and brake booster failure and quoted repair. This is a serious safety issue because braking became more difficult while driving, including on the highway, with sudden warning lights and degraded stopping ability. The failed components are available for inspection. The problem has now been confirmed by a Toyota dealership. The issue was reported to a Toyota dealership during the prior support-program period but was not confirmed then.
TOYOTA PRIUS ABS BRAKE PUMP ACTUATOR BOOSTER FAILING Making hissing noises and warning icon at only 10 years 9 month, 85,000 miles. Toyota extended warranty is NOT covering.
On Feb. 19, 2026, I went to an auto repair store to change oil. I was told that I need to have rear brake pad and rotor replacement service because my car does not have it. The mechanic showed me and said that I only have the front brake work and it can cause safety issue.
Inferior brake system on 2015 Prius master brake cylinder and vacuum booster. Extended warranty issues identified by Toyota for 10 years or 150, 000 miles. I bought my Prius used in 2021 with 92,000 miles at age [XXX] old intending it to last as long as I did. I am now [XXX] old and essentially totally independent. The above mentioned parts were identified as not functioning properly on 2/3/2026 (mileage 139, 106). On 2/6/26, I took it to Goettle Toyota, Ocala FL (mileage. 139,160) knowing there was an extended warranty program available that was admitting the parts were defective but not worthy of recall. I was advised the warranty for my vehicle expired 10/26/2025 (3 months and 8 days prior) and was now invalid. Brake replacement cost is $3675.00 + tax🥴. I was provided warranty information and instructed to call Toyota. I called, spoke with Brook and was advised the warranty was invalid due to date even though the car has less than the 150, 000 mile covered and nothing could be done. I was never notified of this issue so I could monitor for problems before the expiration. Average life for these items on a Prius is 250,000 miles, not 139, 000. I am on limited, fixed income and cannot afford this unnecessary repair. I am already gladly driving a 10 year old car to be independent. Loss of transportation changes my entire lifestyle. I cannot afford another car (if I could, I would be fixing this one). I would be reliant FOR THE REST OF MY LIFE, on others for all needs outside of my home. I live in a very rural area. I feel since I was NEVER notified of any issues and the car is LOW mileage and there should be another 100,000 miles on this car (I have driven it less than 50,000 miles in 5 years) that Toyota should honor the extended warranty based on the proximity of the malfunction to the ending of the warranty period and the LOW MILEAGE of the vehicle. This amount of money is NOTHING to Toyota but it is LIFE CHANGING to this, up until now, independent woma INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFOR
The brake booster suddenly fails at 54k mile. Brake responds slower and need to push the brake pedal all the way It seems a lot of 2010-2015 Prius are facing this problem ABS light, skid light, and brake light was on when it happened, first appeared on Feb 6, 2026 Have to replace brake boost for ~$1500
The contact owns a 2015 Toyota Prius. The contact stated that while driving at an undisclosed speed, the ABS and the traction control warning lights illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed with a leak in the brake fluid hose. The contact was unsure what repair was performed, but the vehicle was repaired. The contact stated that the failure reoccurred with an abnormal sound. The vehicle was taken back to the independent mechanic, and the contact was informed that the vehicle needed to be taken to the dealer for a complete diagnostic test. The vehicle was taken to the dealer, where it was diagnosed with brake booster failure. The contact was informed that the brake booster needed to be replaced. The vehicle was not repaired. The contact was notified of Customer Support Campaign: ZJB; however, the contact was informed that the repair was not covered under the Customer Support Program because of the 10-year 100,000-mile limitation. The manufacturer was made aware of the failure, and a case was filed. In addition, the contact stated that the Customer Support Program: ZJB, was mailed out to customers 10 years ago. The contact stated that the information was never received. The failure mileage was approximately 114,000.
ABS break actuator and abs pump failed while driving losing loss of breaking. Toyota is aware of this problem but refuse to fix this notorious and dangerous problem they have with multiple model years. I was not informed of the limited service campaign. This should be recalled as a safety to the public.
Defected brake booster hard brake suddenly car less than 100 000 miles many vehicles with the problem
I purchased a vehicle a year ago whenever my vehicle was still under the tenure and the 10 year and it’s still under 150,000 mile range. The vehicle was purchased strictly from the Toyota dealership in Lakeland, Florida, and shortly thereafter my brakes completely went out and the booster actuator assembly looking it up by further realize that is a very common issue and that there is so much that there’s class action lawsuits and also instead of it having a recall, it has a customer support to replace parts. My car is very dangerous and doesn’t have any brakes and it’s still very new from the dealership. What it’s very interesting is that it’s not throwing any codes at all, though it beeps the entire time that I’m in the vehicle with the ABS light on and I know that it’s that problem why is it not showing any codes I think that for sure, the dealership would’ve had to done something to prevent that in order to sell the car unsafely
While driving, my brakes became mushy and ineffective. Brake warning lights came on, also. It was very scary driving in rush hour traffic with little to no brakes. There was no reliability. Just keeping as much as possible space between cars, using Hazard lights &prayer.
The ABS failed while driving on the highway. There was no accident, but it was substantially harder to brake when needed.
This vehicle has 95k miles, now the vehicle has a brake problem which can cause deadly problems. The parts that have gone bad on this car are defective parts that toyota knows about. The warranty they extended for this ended in 02/2015. They had 150k miles or 10 years limit on that warranty. We are well under the mileage and 10 months over according to toyota. Can’t believe they will dismiss something this delicate and dangerous. The parts are not cheap and it’s something we can’t afford to fix right now. I can’t believe Toyota will just wash their hands on something this important in a vehicle. This is a know defective part! They should have some sort of responsibility and resolution. I called and was told they cant do anything. Even a part offer so we can fix nothing. Please review this and hopefully you can help.
The vehicle has 95k miles on it and both brake actuator assembly and booster pump have gone bad. This is a defective issue, I called toyota and was told too bad since the program that fixed this ended 02/25. The car met the mileage requirement, but being 10 months out of the date gives toyota the right to wash their hands on a defective part. The part is over $1500 just in parts to replace! This is wrong on their part. Not one option offered.
The brake accumulator went out thanksgiving day on my way home nearly causing an accident. I also missed dinner due to the issue creating a clearly unsafe driving condition where I was barely able to use my brakes. This is a known issue by Toyota, whom extended the warranty to 10 years. Of course, my warranty was 3 days past the 10 years even though it is under the mileage requirement. This should have been a recall, as it is a known and reported problem. I am now out 3300$ for the repair just to get my car in an operable condition. There were no warnings, the abs light as well as the traction alert went off and I lost the ability to properly brake in an instant. There was no warning, nor was I notified about this part.
Hi, I am reporting a brake system failure on my 2015 Toyota Prius. In July 2025, the ABS and brake warning lights suddenly appeared, and a Toyota service center confirmed it is the known Prius brake system defect. The repair estimate ranges from $4,502 to $27,814, but Toyota declined coverage because the vehicle is just past the 10-year warranty limit. This issue poses a safety risk due to reduced braking performance. 1) The brake system / ABS actuator assembly malfunctioned. and yes, the component is still installed in the vehicle and available for inspection upon request. 2)The ABS is no longer functioning properly, significantly increases the risk of losing control or extended stopping distance, especially in wet or emergency braking conditions. I rely on this car for daily transportation in a car-dependent area, so this issue directly affects my ability to drive safely and could endanger others on the road. 3)Yes. The issue was diagnosed and confirmed by an authorized Toyota dealership center. 4)Yes. The vehicle was inspected by an authorized Toyota dealership only. 5)Yes. The ABS light, brake warning light, and other dashboard indicators suddenly appeared in July 2025.
The Brake Booster system failed two weeks after the Toyota Customer Confidence Program for that condition ended and they will not reimburse me for a $3000 repair. I knew there was a problem because all the dash lights came on at once while we were driving on a highway. I had it towed away to be repaired and it was found that the brake booster system was failing. Had I ignored it or not acted as immediately as I did the brakes could have failed while the car was in use and hurt or killed me or someone else. They should issue a recall for this condition and fix it for Prius models that still need it and they should reimburse me.
The ABS, BREAK, and Traction Control, suddenly turned on when I was traveling on the freeway in mild traffic. I was traveling at about 60-65 mph. I attempted to use the breaks and could feel a substantial difference in how much and how hard I had to push in order to stop. The problem has not been confirmed by a dealer or service center. The vehicle was inspected by my brother in law who works on cars frequently. There were no warning symptoms prior to the problem. The problem first occurred on Saturday November 1st at about 12:30. According to my brother in law, it was the break pump that failed; you can hear air escaping when you push on the break pedal.
The contact owns a 2015 Toyota Prius. The contact stated that while driving approximately 15-20 MPH, the ABS, brakes, and the traction control warning lights, and the malfunction indicator light were illuminated. Additionally, the vehicle hesitated to respond while depressing the brake pedal, causing the braking distance to be extended. The vehicle was taken to the dealer, where it was diagnosed with an abnormal leak in the accumulator and a leak in the brake booster pump. The dealer determined that the brake master cylinder and the brake booster pump needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 94,100.
On or around 9/13/25 my ABS, Brake, Traction and Emergency Sign sensors turned on in my 2015 Toyota Prius. I noticed that my brakes became squishy and when I drove, it took longer for my car to brake (there was more distance in my braking ability to stop the car). My car also felt a bit more airy than it usually does when I drive it. I took it to 2 independent car repair shops for a diagnostic and both told me that the ABS C1391 code came up. Soon thereafter, I took it to a local Toyota dealership for a diagnostic and was given the ABS C1391(code) Abnormal Leak in the accumulator. The Toyota mechanic informed me that that when he did the diagnostic, the TSB 0024-19 code came up on his end, which means that Toyota alerts their mechanics of the necessary procedures to implement for this problem, as it's a known Toyota problem and defect: 1) Remove & Replace the Brake Booster Assembly w/the Master Cylinder (apparently the master cylinder goes out too since they're connected) and 2) Remove and Replace the Brake Booster Assembly Pump. Toyota's estimate to repair it is $4,404.72; I can't afford this and need a car. It's my only car! I did research and learned that this is a known Toyota issue for Prius (2010-2015) and a Customer Support Program w/an extended warranty was issued to cover the full cost. Despite this, their extended warranty expired for me on 12/29/24, despite me meeting the other 10 yr or 150K or less mileage criteria. Despite filing a complaint with Toyota's Resolution Center they refused to extend or offer warranty or any payment for a KNOWN Toyota defect, saying my issue was "after the extended warranty date" and there "isn't a recall." I'm disgusted to say the least about this, as Toyota is well aware of this car part defect which is a safety hazard and liability for its customers. Something must be done about this. It's unfair and not equitable to have loyal Toyota customers absorb the cost of known safety hazard defects by Toyota and risk lives.
Brake Accumulator and Master cylinder has failed. All lights for the ABS, TSC, and VSC are iliuminated
Before, I was driving and occasionally the traction control light would flash when I put my foot down on the brakes but would go away when released. I didn't think much of it but then a few days later, I went to brake to stop the car and then the abs, traction control and brake system lights lit up on the dash and wouldn't go away. I pulled over safely and turned the car off and on again but it wouldn't go away. The brakes were also noticeably more firm compared to before as it was quite squishy but now it was solid and all regen braking went away and it appeared I had no more ABS which could lead to a collision. I immediately took it into the dealer to have it diagnosed. I did some reading and if I kept driving with this problem, eventually the brakes would fail and collapse completely and leave me unable to stop the vehicle. At the service center, they were able to read the code DTC C1246 and clearing the codes did not work. The part that was replaced was the brake booster and the brake master cylinder and the brake pedal stroke sensor. It appears that a warranty program exists for this issue but it is not a recall. I am also not sure if the part that was replaced is a revised part that will no longer have this issue or there is no change in the part design. I believe this is a massive safety issue and should be a recall and not a warranty replacement program as every prius should be recalled for this defect. I was very close to being out of warranty and if I had taken any longer to bring it into the dealer I would have been out of the extended CSP warranty. Even the dealer initially thought I would be out of warranty but I had to argue that I was in warranty and should be eligible for a warranty replacement and that I should not need to pay for a diagnostic fee despite it not being a recall.
Got the warning code for C1391 for the brake booster. It failed at 140k miles but because it failed past the 10 year mark did not qualify for the Toyota extended warranty program. I don't think the warranty program is good enough and should be addressed as a recall. I had sudden total brake failure on the highway which could have been extremely deadly.
The contact owns a 2015 Toyota Prius. The contact stated that while driving at various speeds and depressing the brake pedal, the brake pedal went to the floorboard, and the vehicle hesitated while responding. The traction control, ABS, BRAKES, and cruise control warning lights were illuminated. The vehicle was taken to Gasket Masters Inc, where it was diagnosed and determined that the ABS assembly was leaking fluid into the braking system, and the ABS module had failed, causing the brake pump to fail. The vehicle was not repaired. Additionally, the malfunction warning light was illuminated. The vehicle was taken to the dealer, but was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 186,000.
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