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.
2010 Toyota Prius brakes complaints
Page 2 of 66: complaints 11 to 40 of 1,945, newest first, as owners wrote them.
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.
The contact owns a 2010 Toyota Prius. The contact stated that while driving 70 MPH, the vehicle jerked, and the vehicle failed to accelerate as intended while depressing the accelerator pedal. Additionally, the steering wheel seized, and the vehicle stalled. The contact pulled over to the side of the road, opened the hood, and disconnected and reconnected the battery terminals to reboot the vehicle. The contact stated that a yellow triangle warning light and the check engine warning light were illuminated. The message "Check Hybrid System" was displayed. The contact was able to restart the vehicle; however, the vehicle failed to exceed 65 MPH while driving. The ABS warning light was illuminated. The contact took the vehicle to Auto Zone and O'Reilly's; however, no cause for the failure was found. The vehicle was then taken to the dealer. The contact was informed that the failure might be an ABS system failure. The vehicle was not repaired due to the cost. The contact stated that the failure first occurred years ago, and the failure persisted. The manufacturer was not notified of the failure. The failure mileage was unknown.
The contact owns 2010 Toyota Prius. The contact stated that while depressing the brake pedal, the ABS, brakes, and the vehicle stability control warning lights were illuminated. An Independent mechanic was contacted. The vehicle was taken to an independent mechanic where it was diagnosed and determined that the brake booster and accumulator needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact that the VIN was not included in the recall; however, the recall had expired. The failure mileage was 172,000.
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.
The brake and pre collision system suddenly fail without warning.
Have multiple warning lamps that light up on and off and the brakes in my car get spongy making the braking unsafe. The lights that turn on are the steering/ traction , brake, and abs light. There are multiple complaints online on YouTube from similar issues ongoing and no recall made. My mechanic says it indicates a leak however there is no brake fluid missing and on YouTube there’s work arounds because people keep getting the same message, yet no recall has been made. This can affect steering and cause an accident. Please recall soon. Including YouTube link so you can see all the comments and issues from thousands that don’t know how to report but view to fix temporarily. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
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.
It is a known problem that Priuses manufactured from 2004 to 2015 have issues with the brake master cylinder and brake booster accumulator. When the vehicle computer recognizes an internal leak (ABS C1391) or other issue in the accumulator pump, it completely disables the regenerative braking system, which significantly reduces braking power. In my case, the problem is intermittent, and the vehicle computer will occasionally clear the code and operate normally. A slight whirring sound can still be heard (indicative of an internal leak), leading me to conclude that the part is still damaged, even when the code clears itself. This continues to affect my and my passengers' safety because the problem comes back with no warning while driving. Many times at highway speeds, the regenerative braking system will shut off while decelerating. This has caused scares and near-accidents. Imagine you are approaching stopped traffic while traveling 65 miles per hour. You press the brake to start slowing down, and while decelerating, the dashboard lights up and the brake pedal goes spongey. Now, you must slam the brake all the way into the firewall to engage the disks and pads exclusively. Aside from the imminent terror of hitting the car in front of you, now you are skidding on the brakes, worried the car behind you will crush the rear. Sooner or later this will cause somebody to get into an accident when a split-second decision cannot to be made quickly enough. The issue is well-known, and a warranty recall was issued, but it does not cover any vehicles over a certain age and mileage. It has been reproduced by my local mechanic and inspected by a Prius specialist, who both quote about $3800 to fully replace and recalibrate the failing parts. There were no indicators of this issue before it happened to my wife and I the first time on the highway. While I am grateful that nobody was injured, the situation could be completely different had the problem occurred just seconds later.
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.
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
The contact owns a 2010 Toyota Prius. The contact stated while driving 45-50 MPH and depressing the brake pedal, the ABS, the traction control, and the check engine warning lights were illuminated. The contact stated that the vehicle experienced reduced braking power and the vehicle failed to respond as needed. The contact stated that upon engaging the brake, the vehicle decelerated, and the contact pulled to the base of an inclined side street, where the vehicle was able to stop. The contact was able to safety park and inspected the vehicle. The contact was able to drive to the residence at slow speeds. The vehicle was taken to the dealer, where it was diagnosed that the brake booster and master cylinder had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 94,000.
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.
Toyota issued a recall with a limited time for Prius brake booster/actuator failures. This issue is known to present brake failures and necessarily place drivers, passengers, and pedestrians at risk in the case of such brake failures. Toyota made no effort to proactively remedy this problem and further neglected customer safety by excluding Priuses with the same manufacturing issue from the recall, under its 10 year 150,000 mile requirement. Whether or not the Priuses have been driven 150,000 miles or 10 years the nature with which the malfunction presents represents a safety for any driver.
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.
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.
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.
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 the federal safety agency.
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.
My ABS system light is on. The Toyota mechanic has determined that it is due to Nitrogen gas from a component of the brake booster pump assembly could leak into the brake fluid. As nitrogen is released into the brake fluid, the brake pedal may have reduced hydraulic pressure. Under certain circumstances, this condition could affect stopping distance and increase the risk of a crash. Toyota recalled model year 2010 Prius vehicles manufactured March 31, 2009, through October 9, 2009. I took my Prius to Toyota to fix this ABS recall problems but they are refusing to fix the problem for free. They are charging me $4000 to fix it.
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.
- 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)
I am writing to express my concern regarding an issue with the PCS System dash lights on my 2010 Toyota Prius. I recently became aware of problems related to the brake booster system, which I understand have been addressed through recalls or warranty extensions on certain models. I believe that the issue I am experiencing should be covered under warranty, and I kindly request your assistance in resolving this matter.
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.
Brake booster, brake accuater went out even after the recall. Dealership said they could do nothing to help
While driving at a high speed in the left lane of a 2 lane interstate a car in the right lane merged into me. Luckily I was able to brake in time to avoid a collision, unfortunately the sudden braking at a high speed caused my car to loose all control. Upon braking my front tires lost all traction and shifted my car to the right, I remained horizontal sliding across the highway for an unrecognized distance (my guess is 10-20 meters), before shifting another 90 degrees to the right leaving me backwards. At this point I had shifted across both lanes and the emergency lane, I was backwards in a grass border on the right side of the interstate. If this had been any other sort of barrier I may not have Lived. This incident has not been reproduced or confirmed by a dealer or independent service center. The vehicle had recently had its worn brake components replaced in response to a similar incident happening, which I first attributed to worn brakes— this theory was supported by the brake technician prior to service. I have had a tire pressure light on since I purchased the car, but this was explained to me as a malfunctioned TPS.
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 the federal safety agency 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 the federal safety agency 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)
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 lights on, traction light on .Actuator running cicle constantly . Breaks felt spongy
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