2010 Toyota Prius Brakes

In 2019 Toyota repaired my 2010 Prius(120,189 miles) braking system under the ZJB program. The brake cylinder assembly and brake booster pump assembly were replaced as they had a known defect that caused the braking system to fail. As of February 27, 2026 the replaced components are failing again. The auto has approximately 224,000 miles. So the replacement components failed in less miles and time then the original equipment failed which was determined to be faulty. Toyota has declined any assistance in the matter.

On November 25, 2025, at approximately 11:45 p.m., our 2010 Toyota Prius experienced a braking system malfunction during normal operation. The brake pedal required significantly increased effort and the vehicle exhibited reduced braking performance, indicating a loss of brake power assist. The vehicle required increased stopping distance, creating an immediate risk of a collision. At the time of the failure, multiple warning indicators illuminated simultaneously, including the brake system warning, ABS warning, check engine light, battery warning, steering warning, tire pressure warning, and vehicle stability control/slip indicator. There were no warning lamps or abnormal symptoms prior to the failure. The failure was determined to involve the brake booster pump assembly, a component responsible for maintaining hydraulic brake assist pressure. This component is known to experience internal accumulator housing degradation, which can allow nitrogen gas migration into the brake fluid and result in partial or complete loss of brake assist. The affected component remains available for inspection. Following the incident, an authorized Toyota dealership inspected the vehicle and reproduced and confirmed the condition. Service records indicate the brake booster pump assembly had previously been replaced under a Toyota safety recall. Despite this prior recall repair, the same component failed again after approximately 41,000 miles of service, demonstrating that the recall remedy was ineffective. As a result of this failure, the vehicle was rendered unsafe to operate. Despite dealer confirmation that the malfunction involved a previously recalled safety component, corrective repairs were declined, with warranty limitations cited rather than addressing the repeat safety-related failure.

Car keeps throwing a C1391 Abnormal Leak in Accumulator code. The ABS, traction control, and brake lights are all illuminated. Hissing sound from brake pedal. Spongy feel when braking and incredibly soft braking as well, very hazardous to driving and stopping. This is a known issue with the 2010-2015 Prius, and a quick internet search shows thousands of other Prius owners who also have this issue with their vehicles. It’s a safety hazard and can be potentially life threatening. Toyota is not doing anything to rectify this potentially fatal issue that impacts thousands of vehicles and vehicle owners and their families. Estimated cost of repair is upwards of $4,000 and simply not affordable to most consumers. Actions needs to be taken IMMEDIATELY by Toyota to recall these vehicles and fix them.

While driving on the freeway the Traction control light, ABS light, Brake System Light and Brake light all came on. Fortunately I haven't had any issues but when I took it to the a dealership I was told that the Brake booster and pump need to be replaced as the master cylinder was leaking into the brake fluid and given an estimate of $3500 for the repair. People online have said that after having this issue the brakes can go out at any time. I am unable to pay for the repairs at the moment so I have to drive with the knowledge of having my brakes going out at any time.

I purchased a used 2010 Prius on May 1, 2025. On May 5, the car would not turn on. Thought it was the battery. Replaced the battery on May 6. On May 8, the battery was dead again. I jumped the car and tried driving it to the Toyota dealership to have it looked at. On the way a loud beeping sound started and the ABS light came on. I pulled over and noticed the brakes felt strange. After having it towed to Ourisman Toyota, the told me the brake booster was broken causing the battery to drain. The cost for repair is a little over $4,000. This almost half of what I paid for the vehicle.

A few weeks ago, while waiting at a traffic light, the brake warning lights (ABS, Emergency brake, Traction control) lights on my 2013 Prius lit up and the brake pedal suddenly becomes much less responsive. I drove carefully back home, and researched online what the problem could be. To my surprise, this seems to be a known problem to Toyota, who had issued a campaign in the past to address this problem (ABS actuator, pump) and to replace the known faulty parts for free, but only for owners who were experiencing a failure at that time. Now the recall has expired, and owners like me who weren't having a problem at the time are stuck in a situation with cars that have a known, dangerous fault, while Toyota refuses to help with the problem anymore. The approximate cost for replace/repair is over $4000. All owners should have been included in the previous campaign, whether they were experiencing a failure or not, during that time period since Toyota knew that these parts are faulty.

What component or system failed or malfunctioned, and is it available for inspection upon request? Brake Actuator failed requiring replacement of booster assembly with master cylinder and booster pump assembly How was your safety or the safety of others put at risk? This greatly impacted braking and stopping distance Has the problem been reproduced or confirmed by a dealer or independent service center? Yes, Toyota Dealership Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Yes, Toyota Dealership Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? No. These lights appeared after the failure - Brake, ABS, Traction Control

Brakes have failed with a DTC C1391 indicating an accumulator leak. The brake booster pump constantly runs. When the DTC is triggered the brake feel becomes suddenly different as regen braking is lost. Appears to be a very common and expensive repair. Toyota has already had recalls and extended repair program for these parts but they are now expired and not covered.

C1391 error, "Abnormal Leak of ACC PRESS". This is a common failure in many prius and requires the replacement of the brake master cylinder and brake accumulator. Toyota has an expired customer support program but no actual recall. Parts were replaced to bring braking system back into working condition.

Code diagnostic C1391 ABS system. I have replaced this in my previous 2009 Toyota Prius, it has been replaced in this 2010 Toyota Prius, and now needs to be replaced AGAIN in the 2010 Toyota Prius. It’s incredibly dangerous, no warning signs, spongy brakes all of the sudden that barely feel like they’re going to work. It puts not only myself in danger, but others especially when it just happens without warning and all of the lights come on as you are driving and the brakes become extremely wonky.

My brake booster master cylinder and pump assembly went out while driving on the freeway. My brakes became soft and unresponsive, though I was able to exit the freeway without incident. My ABS light, brake light, and traction control lights all came on. The lights have since remained on and my brakes continue to malfunction. My local repair show diagnoses the issue with the diagnostic trouble code: C1391 Back in 2018, before I owned the car, Toyota offered an "extended warranty" to have the parts replaced for free for 10 years or 150,000 miles, whichever came first. I'm past the year threshold but well short of the mileage one. I feel a recall should be made and the repair covered, as this is clearly a safety issue.

I recently had an issue with the brake actuator on my 2010 Toyota Prius, showing error code C1391. This caused reduced braking efficiency, and research shows it’s a common safety concern with Priuses. While there was a recall, it has expired, leaving owners like me without support. I kindly request an investigation to address this critical issue for the safety of all affected drivers.

- Brake system failure - Safety risk due to longer stopping distance - Problem was reproduced and confirmed by two repair shops - Components were inspected by repair shop - Several brake warning lights were ON on dashboard AFTER failure occurred. Toyota recalled 2010 Prius vehicles for Brake Booster and Brake Booster Pump assembly failures. Recall code D0H. Toyota claims that the replacement parts are fixed for the gasket leak issue. Toyota replaced these parts on my car in 2013 as part of the recall. The replaced parts labeling are verified to be the claimed fixed ones. But only about 62,000 miles after the D0H repairs (odometer at 81,400 miles) the parts failed again on March 20, 2015. I do not put many miles on my cars. Toyota has put a maximum repair date for this issue knowing failures keep re-occurring (No repairs supported after 2019). Toyota has not fixed this issue given the repeat failures. Repairs for this issue is extremely expensive at more than $4000 at independent shop (parts and labor)

One day after arriving home from work, all the sudden my ABS light, BRAKE light and traction control light turned on, my brake pedal being harder to push, and my car making weird humming noises every 5 seconds. Upon taking my 2010 Prius to my trusted repair shop, it was revealed that my break actuator was faulty. I drive on roads that need this part to WORK! Especially in the height of construction going on PA. One of the roads that I take has been milled up and upon driving on that road I nearly swerved onto the side walk 3 times! My breaking has been harsh and with one incident that nearly didn't break in time at all! Doing research and looking into the active investigations on this part, it turns out I am one of possible thousands who are dealing with this issue that has all been tied back to the break actuator being faulty which is very expensive to even repair for something that is obviously a poor design.

I drove the car to my destination without any issues. An hour later, when I restarted the vehicle to leave, the following dashboard lights were on (slip indicator, ABS warning light, and brake system warning light). When I drove the vehicle, the brakes had diminished stopping power. It took farther for the vehicle to come to a full stop when applying the brakes. When we had it checked by the Toyota dealer we were informed that there was an abnormal leak in the accumulator assembly (system diagnostic code C1391) and it would need brake booster/master cylinder assembly with accumulator pump replacement.

The ABS, Brake, TSC lights have all appeared on the dash. When running the OBD codes, the error C1391 appears indicating a problem with the ABS pump. When under the dash with the vehicle running, one can hear the abs pump engaging every few seconds which is not normal. After resetting the code. The error quickly pops back up. This is a known problem with this model Prius that Toyota is aware of. Toyota has NOT put out a safety recall for this issue. They refuse to make the repair of a faulty designed abs module, which is obviously a safety concern. The vehicle currently has 128000 miles with no other issues.

Dear NHTSA Team, I am filing a safety complaint regarding my 2010 Toyota Prius (VIN: [XXX] ) due to ongoing brake system failures. My vehicle is affected by Safety Recall D0H (Brake Booster Pump Assembly – Accumulator), but Toyota refuses to replace all necessary components for a proper repair. Issue Summary: •My brakes have intermittently failed, requiring excessive pedal pressure and causing delayed stopping, putting me at serious risk. •I took my car to Toyota on Edens for the recall repair, where Service Advisor David confirmed that the brake booster and accumulator should be replaced together. •However, Toyota will only cover the accumulator under Recall D0H, despite the brake booster being critical for safety. •My vehicle has Diagnostic Trouble Code (DTC) C1391, indicating an internal leak in the braking system, but Toyota refuses to cover the booster replacement. Toyota’s Response: •I contacted Jessica from Toyota’s Customer Experience Center (Case Number: [XXX]). •Toyota refuses to replace the booster under the recall, leaving me responsible for the cost, even though the dealership confirmed it’s necessary. •This decision leaves my car in an unsafe condition even after the recall repair. Request for NHTSA Action: 1.Investigate the safety risks related to this recall and the necessity of replacing both the booster and accumulator together. 2.Ensure Toyota properly covers all necessary brake repairs for affected vehicles. 3.Expand or modify Recall D0H to include the brake booster, as it directly affects braking performance. I urge NHTSA to take action before this defect leads to accidents or injuries. I am available to provide additional information as needed. Thank you for your time and attention to this urgent matter. Sincerely, [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Abs lights on, traction light on .Actuator running cicle constantly . Breaks felt spongy

Break booster fail. Will cause the breaks to fail. There was a voluntary recall on these but I never recieveed the letter in the mail. Thr break booster failed after the voluntary recall was up. Toyota said they cannot help with this. Other prius owners i talked to have the same issue with their 2010 prius break boosters and also did not get the letter in the mail.

ABS Pump/Motor failed. Lost power and control over the breaks . ABS light on

I was coming to an intersection where two cars were waiting for a right turn. I pressed on the brakes and nothing happened. The car continued to move without slowing down. The brakes felt "blocked" and unresponsive. I engaged the manual break at the last moment and that slowed me down. But I still hit the car in front of me which in turn hit another car in front of it. The police report says "following too close". But I was not following other cars. The two cars were already at the intersection. I was just coming to this intersection and attempted to slow down as usual. Except that the brakes did not respond. My car was a total loss.

We have a 2010 Toyota Prius. All the sudden we got errors/warnings on our dash about ABS and traction lights, and brake light, staying on all the time. Brakes extremely sluggish, and from doing research advised not to drive it. Toyota did a diagnostic test which came up as C1391, bad ABS booster pump and master cylinder. This is a huge safety issue, others have reported brakes completely going out on the highway, and also reporting Toyota is not paying for fixing the issue, and only "certain Priuses" meet their criteria to pay for repairs. There supposedly was a recall at some point but we NEVER received it. I have contacted Toyota America and waiting to hear back. It is going to be very expensive to repair, about $3500-$4500. Yes, it is a 2010, but from what I'm reading and hearing is a MAJOR safety issue and Toyota needs to be held responsible and honor/extend any and all recalls. Again, I'm waiting to hear back from them, but was advised by many other Prius owners to file a complaint with NHTSA.

ABS, traction, and brake warning lights came on. No OBD code reading. Mechanic says needs brake booster pump; brake booster master cylinder. Theoretically mine were serviced but no way for me to actually verify it happened on the recall. Vehicle located in Kamuela, Hawaii.

My brakes stopped braking but luckily I could drive slowly into a curb in my neighborhood. God knows what could’ve happened if I was on the freeway. All the dash lights came on at the same time so I ran some codes; it came back C1391 - the brake actuator is broken. Toyota will not cover it despite this being a very common issue. My car is undriveable until this gets fixed because it will not break.

Please read the attached file "prius complaint signed" for a full description. I am the owner of a 2010 Toyota Prius, 2ZR-FXE. The warning light came up on my dashboard of my vehicle, so I took my 2010 prius to AutoZone, to get a free diagnostic. The diagnostic indicated the problem code of “C1256” “Accumulator Low Pressure” for the “Anti-Lock Brake System.” See Ex. A (AutoZone Diagnostic). It is available for inspection. According to the safety recall number “D0H”, 2010 prius model “2ZR-FXE” has a “Brake Booster Pump Assembly which can develop a crack inside the accumulator housing. If this occurs nitrogen gas could leak into the brake fluid and gradually cause a loss of power assist. Under certain circumstances, THIS COULD AFFECT STOPPING DISTANCE AND INCREASE THE RISK OF A CRASH.” (Emphasis added). I have noticed that when I brake hard, IT TAKES LONGER TO COME TO A STOP, WHICH THREATENS NOT ONLY MY LIFE, BUT THE LIVES OF MY WIFE AND TWO [XXX] DAUGHTERS WHO ALSO RIDE IN THIS VEHICLE. According to the safety recall, “Toyota dealers will perform an inspection and, if necessary, replace the Brake Booster Pump Assembly at NO CHARGE to the vehicle owner . . .” See id. The safety recall does not explicitly permit dealers or servicers to charge for an inspection with regards to this defect, according to the information provided me. The estimate, provided by DARCARS recommending replacement of the “BRAKE BOOSTER WITH MASTER CYLINDER WITH PUMP[,]” confirms that the issue appears to be that which is covered by the safety recall. Ex. F.; see also Exhibit B Safety Recall (The vehicle has a “BRAKE BOOSTER PUMP ASSEMBLY WHICH CAN DEVELOP A CRACK INSIDE THE ACCUMULATOR HOUSING . . .”). See also Exhibit E Error Code from DARCARS (“C1256 Accumulator Low Pressure”). Nevertheless, DARCARS refused to waive the diagnostic fee of $150 and would not repair the vehicle unless I paid them “$5,150.” See Exhibit F. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)