2011 Toyota Prius Brakes

While driving, the Brake, ABS, traction light and other light lit up. The car lurched in an odd way. I can hear the oil pressure pump turn on every 5 seconds. Toyota shops told me the master cylinder and booster pump are failing and that the brakes will stop working while driving, causing an accident.

The abs, brake, and traction control are intermittently on and off recently. I thought that there was a visible leak in the brake fluid. But my mechanic said that there was no feasible leaks found upon inspection. The car has also been inspected in Maryland without any issues. I came across many forums that said that this is a common issue in Prius. My safety was at risk if this is due to internal failure or defect of the product, especially because I drive with my [XXX] almost everyday to take her to daycare. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ABS, Slip Indicator and Brake warning lights have appeared on the cars dashboard. DTC fault code C1391 has appeared indicating a failure of the Brake Booster and Brake Booster Pump assemblies per Toyota Customer Support Bulletin (ZJB) No.: POL18-03. Loss of regenerative braking, putting the safety off occupants at risk.

There were not any prior problem with my 2011 Toyota Prius' brake but it started making air pumping noises when I brake which makes me very nervous to drive my car. A local mechanic confirmed that the problem is the faulty brake booster assembly and pump. Toyota issued Customer Support Program for this problem but covered only up to 10 years from the first date of use. Although my car has less than 120,000 mileage, I have to pay for this repair and it will cost me close to $2500 at a local repair shop! I want to go to Toyota dealership to fix but their cost is going to be even more! According to online research, many Prius owners have this same problem and have to pay out of their own pockets. This is unacceptable. Toyota should put a recall on this problem and cover the repair cost!!

The ABS actuator on my 2011 Toyota Prius has failed, which is a known and common issue with this generation of Prius vehicles. The component causes abnormal brake pedal feel and inconsistent braking performance. The vehicle has been inspected and diagnosed by a Toyota dealership, who confirmed the ABS actuator assembly needs replacement. This failure poses a serious safety risk because it affects braking reliability and increases stopping distance, especially during sudden stops or wet road conditions. There were no warning lights or messages prior to the failure. The vehicle is available for inspection upon request. The problem has been confirmed by the dealership service department but has not been inspected by the manufacturer, police, or insurance representatives.

Have continuous display of ABS , Brake lights for some time. Diagnosed as problems of ABS brake booster and pump. Toyota recognizes this issue but will not replace it.

My ability to break unexpectedly stopped working while I was on the highway during morning, rush-hour. I was going 55 mph on the highway at the time and luckily, I was on an uphill incline when they went out, thus allowing me to be able to ‘naturally’ slow down. But had I not been on an incline at that time of the brakes faulting, I would have 100% caused a wreck because I could not break at all. My emergency breaks weren’t even working, which is confusing because I thought that was the whole point of the emergency break, was for if your regular brakes become faulty… But NONE of my brakes worked. Which has created a new fear I didn’t know could happen while driving… Also, all the lights that have to do with the breaking system were on (ABS, Traction control, BREAK lights). And a consistent building up hissing noise under the hood.

The Master Cylinder started failing while I was driving the car, the car only has 138k miles, the dashboard lit up like a Christmas tree, all the warning lights were on, and when I went to step on the brake, I had to push it all the way to the floor for any braking to happen. I remember being scared for my life because I had almost no brakes which I could've got into a serious accident or been killed had it failed completely. I took the car to the dealer and they diagnosed it with code C139: Abnormal Leak at Accumulator Assembly, and recommended a new Brake Booster with Master Cylinder Assembly and Brake Booster Pump Assembly with Bracket. The car by age was not in Toyota's extended warranty on the parts but mileage-wise it still is, so I was footed with a $4-5k bill to replace both parts.

I' m getting ABS warning light. Dealer confirmed that I need to replace Brake Actuator and Accumulator which costs me over $3K. Dealer refused to cover under warrant though it's a known issues with TOYOTA PRIUS vehicles.

ABS warning system on dashboard is intermittent. I hear computer noises near the front driver tire. Then the warning light goes out or reappears on dashboard. Issue is the expensive diagnostic fee that may not unearth the cause, and if cause identified the diagnostic fee cannot be applied to the expensive repair. That’s a hard pill to swallow —and not affordable given economy, and I just had all four tires replaced along with a wheel alignment. Also, the yellow tire pressure light now blinks non-stop. (Previously it blinked 3x then stayed on but stopped blinking.) Anyways, Lots of covo about same issue in the 2011 Prius chat room I found after googling “2011 Toyota Prius ABS warning system.” Wondering if software needs updating, or perhaps there’s a systemic mfg defect?

VIN: [XXX] Year/Make/Model: 2011 Toyota Prius Mileage: 87,433 Date: 11/4/2025 DESCRIPTION Sudden 80% brake loss. Loss of ABS Brake Light + ABS + Traction Control lights on dash (photo attached). Known failed brake actuator (C1391) — identical to 500+ complaints in PE19-004. Toyota corporate denied coverage (email attached). This is a SAFETY RECALL issue — please reopen investigation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ABS Brake pump booster and actuator broke and got me almost into an accident. It's a known issue and it's a safety issue because car can still run but the brake is less sensitive. Please get Toyota to honor the repair.

My brakes suddenly stopped responding correctly as I was pulling up to a busy road. My car went part way into traffic and I was nearly hit. After speaking to my mechanic and my local Toyota dealership, I was informed that there was a know issue with the Brake Booster and Hydraulic Accumulator on this vehicle and that Toyota had extended the warranty several times but that it no longer covered my vehicle. They never once acknowledged the safety issue and I was never notified of the risk. I believe the extended warranty was setup to avoid a recall and hide the risk. I firmly believe a recall should be done on these parts and owners should be notified of known safety risks this presents.

While driving on the interstate, the "brake", "TCS", and "ABS" lamps lit up. The brake pedal was stiff and couldn't be depressed. The vehicle initially did not decelerate while attempting to push down on the brake pedal. While maneuvering off the interstate on to the exit lane, the pedal remained stiff however, the vehicle did begin to decelerate. Critically, the amount of time needed to bring the vehicle to a stop was significantly longer than normal. This brake failure could have resulted in a catastrophic, life threatening and/or deadly accident. The DTC associated with this brake booster and pump failure is C1391 which is referenced in TSB-0024-19. This is a known problem that exists in Priuses manufactured between 2010-2015 and addressed by Toyota with CSP(s). The CSP takes a reactive approach to this serious safety concern as owners who "have not experienced the condition described" were informed that "there is no action necessary at this time". The extended warranty of 10 years or 150,000 miles is not applicable to countless drivers who are experiencing this failure caused by "internal malfunctions" outside of this arbitrary time/mileage frame. A letter was sent to the NHTSA on 9/19/19 by the president of Claremont and Capistrano Toyota to petition for the initiation of a Defect Investigation regarding this issue. The letter notes that this brake defect is "causing crashes that are injuring people- and Toyota is mishandling it". The advisor assigned to this repair estimated that they see this issue 1-2 times a month and increasingly, drivers are not covered by the CSP. Toyota is failing to take a proactive approach to this dangerous safety issue by telling owners to essentially wait and see if they experience this failure and then failing to take responsibility for said costly failure should it occur outside of their arbitrary time/mileage frame. This approach to safety is egregious, irresponsible, and unethical and it is putting countless lives at risk.

All brake lights on Dashboard came on. Almost got into an accident because brakes were not responding. Brakes started responding but lights remained on. At time it will contibue to beep and Brakes do not respond. I am seeing that this is a common issue happening to most Prius vehicles after a certain period. It is extremely expensive to repair. Since this is happening on quite a lot of Prius vehicles, I feel this should still be covered by Toyota. This appears to be a faulty Brake Pump and Brake Booster. This has not been inspected by a dealer but being that the car is a 2011, I'm afraid they will decline from what I have been reading.

The brake booster has failed. I was driving, and the ABS, Brake, and Traction Control lights suddenly came on. The brakes felt less powerful. I drove the car Broadway Toyota in Portland, Oregon for maintenance. I was told that the system has failed, and while this is a known issue. It is not currently covered. I was also told that the car is not safe to drive. Toyota had a "Customer Support Program" to cover this issue. However, the program expired on Oct. 8th, 2021. Had I known, I would have brought it in prior to the expiration date. This seems like a recall issue. In Toyota's paperwork for the Customer Support Program, it states that Toyota is aware of "certain internal malfunctions of the Brake Booster Assembly"!

Brake booster has failed. I'm told this is a known issue but no recall has been issued

To whom it may consern, I avoided a situation that could have been a very serious or deadly accident when my vehicle had unusual issue with the vehicle breaking system while driving on the freeway today [XXX]. The vehicle would not stop while pressing on the break pedal and I was able to quickly maneuver the vehicle on the shoulder of the freeway and was able to avoid a deadly crash. Looked on the dash and noticed that ABS, Break, and Traction Control lights all lit up. I was scared for my life and the safety of others around me. The vehicle was towed to my residence since it happened around 10:30pm California time. Quickly did some researched online for any recall on nhtsa.gov website but unsuccessful with any recall regarding the breaking system. I also found out that it is a common problem that other owners have been/experienced with the same vehicle year, make and model. I would greatly appreciate for any information I can gather in order to assist me on how I can get Toyota to look into this issue for the safety of myself and others. It was a very scary scenario that could have been a tragic one that I found myself into. Looking for a prompt response to address this issue. Thank you! INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On our 2011 Toyota Prius there is a complete loss of breaking. The ABS, TCS, and brake lights all came on at one but went off after a few minutes. A few days later the entire system failed when the car was started and now there is no breaks at all on the car. A few months before we took the car to the dealership complaining about a noise when hitting the breaks and was told it was normal and to ignore it. It looks like Toyota knows about this issue and opened a customer care repair program but it expired in 2022 and was not advertised at all so the only way someone would know about it would be if they had an issue. Currently in order to fix the problem we are looking at around $3000 in parts and labor. Looking at other websites including this one the issues appears to be widespread.

Symptoms: The vehicle exhibits a constant and repetitive noise when the brake pedal is pressed. Additionally, multiple warning lights are illuminated on the dashboard, including the red brake light, yellow ABS light, yellow traction control light, and tire pressure light. Suspected Cause: The issue appears to be related to the brake actuator or accumulator. This may be associated with Diagnostic Trouble Code (DTC) C1391, indicating an abnormal leak in the accumulator. This problem causes the brake booster pump to run continuously to maintain pressure, leading to the warning lights and noise. Safety Concerns: The malfunctioning brake system components could compromise the vehicle's braking performance and overall safety. Purchase Details: The vehicle was purchased recently from a dealership, and the issue was not present at the time of purchase.

I bought this car new in 2011, and it is now driven by my daughter. The brakes started having problems around 2019, and the car was taken to Toyota service. It was thought to be a tire issue and the tires were replaced, but the brake issue remained. In February 2024, all the dashboard brake lights came on, and my daughter immediately took the car to Toyota service. The problem was a defective and leaking brake booster pump assembly, a defect well known to Toyota, and the subject of extended warranty on this model (10 years or 150,000 miles) and a recall by Toyota on some other models. Since it was after the 10 year period (despite reported problems during the 10 year period), corporate Toyota told the Toyota dealer service department and our family that they would not cover the $3500 repair bill incurred. This should have been a recall. I am horrified to think what could have happened to my daughter with defective brakes. Corporate Toyota is well aware of this defect. Even a Toyota dealer has previously reported it to the NHTSA. [XXX] . I request corporate Toyota pay for this repair and issue a recall for other unsuspecting drivers of these vehicles. This is a potentially lethal defect that needs a recall, not a post brake failure repair. I send my great thanks to you for investigating this. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

No incident, 3️ Light started recently, traction control, ABS, and Brake light, 07/15/2024. Big O tire did oil change, inspection, claims brake are ok, warning ️ lights comes on and off intermittently, causes brakes when on to become soft pedal when stopping, I consider a defect of workmanship by Toyota on this 3011 model possibly others l. Thank you for your time

Brake actuator failure on the freeway warning lights started beeping had trouble coming to a stop no brake pressure had to swerve to emergency lane. From my understanding there’s a brake actuator recall took it into Toyota my claim was denied .

On April 28, 2024 I was driving when my brakes became squishy and my ABS warning light, red brakes warning light, and traction control light came on. I was very fortunate to be close to my destination and only traveling under 25mph. Roughly a week later it was driven approximately 150ft (on private property) and the brakes were very unresponsive. The car was never accelerated past 3mph for that move. The loss of braking was sudden and happened without any prior warnings. Had I been on a high traffic, high speed road, I believe it likely that this would have resulted in a catastrophic accident. The Master Cylinder Actuator Assembly and Brake Booster Pump Assembly failed. This was confirmed with OBD and a Snap-On Solus Ultra scanner. Both parts have been removed and are available for inspection upon request. They have not been inspected by anyone. I did contact Toyota about the braking issue and they did not express any interest in the issue or inspecting the failed parts. To make my Prius road safe and legal, I needed to replace the Master Cylinder Actuator Assembly and Brake Booster Pump Assembly. These parts were bought from Toyota, who has so far profited from my car's brake failure.

I have been doing some research, and the brake actuator and ABS system failing is a common problem on these cars. Mine recently started acting up and they used to replace it for free. I got my Prius only 6 months ago and have not had any luck getting Toyota to replace it. This needs to be recalled it is a serious safety hazard if the brakes suddenly give out. They should be replacing this free on all cars having this issues and they are aware of the issue (Toyota). The brakes suddenly stopped working well and lights came on in this exact instant on the interstate. This first happened about a month ago. Tons of people are making complaints with the NHTSA for the same issue.