2011 TOYOTA PRIUS Service Brakes Problems

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.

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 purchased a 2011 Prius 4 years ago from a dealership. For the last 2 years, whenever I drive the car, the ABS, brake, and skid lights are on. also, there's a slightly whirring noise every few seconds from under the hood. Braking has been affected, and I've had to increase my stopping distance as a result. Also, the brake pads and rotors deteriorate faster. Apparently, this is a common problem with this type of car. I've called Toyota, and despite it being a known flaw with this car, they refuse to do anything about it.

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.

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.

Toyota issued a Customer Support Program ZJB for extended coverage of the brake booster and actuator assembly (this notice was not sent to the correct address the car was registered to with the dmv in 2019 so I never received the notice for this program) The Toyota program length was for 10 years or 150k miles. My car’s part just failed at 129k which is far below the 150k threshold. Despite being outside the 10 year window I am still under the mileage, the car is in perfect condition and this car is used for work for uber. The malfunction of the Toyota part in my car is a critical safety issue and because it is outside of the program Toyota refused to provide any goodwill assistance

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?

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...

Our trac abs and brake lights came on and braking became more difficult but not totally gone. I took it to my mechanic (not Toyota dealer) and he said the codes were going off for the abs hydraulic system and it would be $3000 to fix! This is unacceptable. I feel like my safety is affected but no one else has been hurt YET. I’m trying to be proactive. they first appeared last month. No manufacturer, insurance agent or cop has inspected it. It can be inspected by appt. Please help

ABS actuator and pump failure

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!!

Brake warning came on and wouldn’t go off. Followed by continuous beeping and now the brakes are no longer working properly. You have to force the brake all the way to the ground to even come to a rolling stop. The problem first occurred on 3/8/25. The brake actuator seems to be a reoccurring problem that Toyota addressed but is no longer fixing. It is dangerous to drive my vehicle and others have said their brakes have completely failed when this problem arose.

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...

In 11/2024, I started experiencing intermittent noises coming from the engine compartment of my 2011 Toyota Prius. The initial sound resembled the buzzing noise generated when first starting the vehicle. Then the noise started to persist for extended periods after the vehicle was turned off. It would oscillate between buzzing for approximately 10 seconds & remaining dormant for about 1 minute, repeating this cycle. The duration of these cycles could extend for up to 20 minutes. Concurrently, I experienced several instances where the brake pedal would abruptly become stiff & difficult to press. Notably, no warning lights were illuminated on the dashboard. Recognizing these symptoms as unusual, I conducted online research and discovered that the issue could potentially stem from a malfunction in the “brake booster pump and assembly.” Given the potential for a loss of braking power and the risk of personal/public safety, I scheduled a diagnostic inspection at...

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.

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.

12 months ago we noticed a vibration while braking at very slow speed/creeping forward that worsened over time. We didn’t understand the significance at the time. In addition, we noticed more recently the brake pump running more and more frequently, even when the brakes weren’t being pressed. We suspect some sort of problem with the brake booster. This has had many claims against Toyota where my break booster is going out, and I have called toyota to assist since they've had a class action lawsuit that caused them to assist with recalls on vehicles; however the year my vehicle does not qualify for a recall. They opened a service case# 241010002348, but told me it would have to be an out of pocket expense since there's nothing they can do. Unfortunately this is a failure defect on the manufacturers production. Please help.

What component or system failed: 47070-47060 Pump Assy, Brake Booster w/Accumulator yes 47050-47150 Cylinder Assembly, Brake Master with Fluid yes put at risk: yes - abnormal braking ABS failure-traction control loss Has the problem been reproduced or confirmed by a dealer: yes Has the vehicle or component been inspected by the manufacturer: Not my specific parts Were there any warning lamps: Yes abs, traction control

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"!

I was driving on a surface street at about 40 miles an hour and then the brakes suddenly don't work. You have to press on the brakes very hard to make them stop. All the safety warning lights were lit up on the dash. Took the car into the Toyota dealership and they said that there was a brake booster and pump customer support program but it's now expired so they won't fix it for free. The brake booster part is about $2000. I contacted Toyota Customer Service and asked them when they sent the notices out for this. They looked up our vin number and said that the notice was sent to the previous owner, since we bought the vehicle used from a Toyota dealer. Spoke to a Toyota supervisor from customer service and told them we never were notified to fix the brake booster. The supervisor said they...

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...

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.

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...

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...

For the past 2 years I've had issues with the ABS, Traction, and Brake lights coming off and on on my dashboard of my 2011 Toyota Prius. Mechanics have replaced various things but have never been able to find the exact problem because the car doesn't either give any codes or it gives codes that don't really say what the exact problem is. I took it to a dealership again today, because not only are those 3 lights on but now the car is beeping continuously, and the dealership told me it was going to be over $5800 to fix the car, that's replacing the brake booster pump and the brake master cylinder, but the only code the car is showing is C1239, no other codes, C1239 is for the rear speed sensor LH. Every time I've had a mechanic/dealership look at the car, they can't find the exact issue...

No incident, 3⚠️ 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 .

As is the case with I am sure thousands of Toyota Prius owners, the brake actuator in my 2011 Prius has failed. The car has approximately 128,000 miles, but given that it is a 2011, the car is outside the Toyota 10 Year/150,000 warranty extension. The deals wants $3,200 to repair. This part should last the life of the vehicle and I am asking NHTSA to help individuals such my myself and force Toyota to make the necessary repair free of charge due to the severe consequences to this part failing.

Driving yesterday on residential street, I gently applied my brakes to stop for a red light. The brakes did not stop the car; pumping the brakes did not help. Dashboard illuminated skidding car diagram, and BRAKE light went on. I took my foot off the gas, rode somewhat on the shoulder, and slowly found a place to park the car. Had to have it towed. No prior warning that the brakes would fail. Dealership advised it was a leak in the brake booster pump or actuator. Later learned that there had been a class action lawsuit dealing with this issue. Also that Toyota had extended the warranty when this happened frequently. I never got a recall notice about this. My car is a 2011 Prius with 59,000 miles. The extended warranty only went to 10 years, and mine is 11 years old, but I haven't seen anyone else in the...

The contact owns a 2011 Toyota Prius. The contact stated that upon starting the vehicle, there was an abnormal beeping sound heard. The contact stated that several warning lights were illuminated. While reversing in the driveway, the brake pedal was depressed to the floorboard before the vehicle stopped. The contact's husband an independent mechanic informed her that the brake actuator needed to be replaced. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was approximately 147,000.

Hello I purchased this s car used on 03/19/24. I was told the brake and Abs light would clear with new battery, which they installed on 03/19/24. It did clear for a couple of miles, brake light warning ⚠️ and abs came on, which causes car not to brake properly, I have not taken car back but believe it and s a defect of the manufacturer's that it has failed. Any help with this issue is appreciated. If you could tell me, what steps I can take to see if Toyota has any extended warranty for this issue Thank you for your Thank you for your time

Brake Booster, pump failure

ABS, Brakes, Traction control lights, and ! illuminated while driving car is under 150,000 miles. Took to an autoshop, Gerald's Tires and Brakes: was told Mastercylinder, booster, accumulator need to be replaced.

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...

The conditions listed in Toyota Customer Support Program ZJB for the brake booster and master cylinder occurred after the 10 year in service date on my vehicle. Brake, ABS, and Traction control warning lights turn on intermittently and when this happens brake response is poor and cruise control shuts off. When applying the brakes an audible tat tat tat sound can be heard from the front of the car that sounds like the ABS being triggered. You should have toyota recall impacted cars and fix the issue as outlined in the TSB and support campaign.

The 2011 Prius has an issue known to Toyota, in which the brake booster pump fails after an indiscriminate amount of time, leading to significant loss in braking ability and control. Toyota knows of this because they issues an extended warranty coverage for these vehicles and this issue, that did not extend beyond 10 years, or 150,000 miles, whichever comes first. [XXX] ) When I was driving my car down Highway [XXX] I lost braking control completely, with a series of constant beeping starting to emit from the braking system. Luckily through mashing the brake pedal and using ebrake I was able to get the car to slow down and pull off the highway. The brakes sporadically and randomly cut in and out with the power braking, leading to uncontrolled stopping power and jerky or inactive braking. There had been lights on the dash indicating the traction system or braking...

Brake warning lights came on, brake stopping has diminished significantly, throwing error codes, attached pictures of the error codes

While driving the car I had three lights turn on the dash simultaneously. The parking brake light, traction control light, and ABS light. The brakes worked but felt spongy and not as responsive as normal. I had it checked out and it has code C1391. The recommendation is to replace the brake booster pump. I was quoted over $2,000 for the repair. There was a Toyota Customer Support Program ZJB that addressed this exact issue. It expired two years ago, and I am now stuck with the repair costs. I believe Toyota should have notified me of this potential danger and/or inspected the vehicle. I meet all the requirements of the bulletin, but it has expired. I reached out to Toyota, and they would not offer any assistance.

The brake system is constantly failing/malfunctioning.It is available for inspection upon request. There has been several incidents where other vehicles have nearly been rear ended. I took my 2011 Toyota Prius (hybrid) to Toyota approximately 8 months ago. They/Toyota did confirm that the problem was indeed the brake booster. The warning lamps did come on soon as the brakes started malfunctioning.

I have a 2011 Toyota Prius with 85K miles, as I was driving on the highway the abs light, brake light, and TSV light came on and then brakes were not working like normal. Had to pump the brakes very rapidly and steer off to the right side of the highway and use the emergency brake to come to a complete stop. I called the Toyota dealer and they said its the brake accumulator fault and they will not cover the fix because it was out of the 10year/150K mile warranty per SB. Towed my car to an independent service center and they confirmed it was the brake accumulator C1391 code. cost me $3000 to fix.

I’ve been told by our machanic that our Prius’ ABS braking system is malfunctioning.

Brake ABS system dashboard lights warning system always always going off for the 9 years I've owned the car. Had the ABS system replaced and still the dashboard lights going off and the system not functioning properly.

I have been experiencing intermittent brake issues with this car now for the last 50k miles. Sometimes the warning lights on the dash will activate, sometimes not when I am experiencing issues. the power assist is the problem. - it activates and then deactivates without warning instantaneously, while applying brakes or not. Sometimes when I am applying the brakes without the brake assist working, it will instantaneously start working without warning, causing my car to almost lock up its brakes. This is very dangerous, especially in traffic. When I apply my brakes at any given time, I never know if I am going to have power assist or not. I have replaced the brake master cylinder once already with a mobile mechanic and the problem went away for about one year but now it is happening again so this seems to be a reoccurring issue with this car. I have...