general problems of the 2012 Toyota Prius - part 2

Toyota installed known faulty brake booster and master cylinder systems in Prius c models manufactured 2012-2014. Knowing these systems would fail, but not wanting to pay for their mistake, they created a basically secret "extended warranty program" for owners to get their brake booster replaced only if for a specific 2 year time frame their brakes failed with a certain dtc code. Knowing that many Prius owners would not actually receive the notification nor had driven their vehicle enough miles for the braking system to fail, they got away without having to correct their issue. The brakes literally just fail and stop working in the middle of the highway, causing extreme safety concerns and accidents with no responsibility from Toyota.

My break actuator goes off every 12 seconds continuously. There is no warning sign in the dash board. Brought the vehicle to the Toyota dealership and had it checked out. The dealership says there is no problems according to their analysis. But the actuator continuously goes off every 12 seconds and the dealership said this was "normal" and charged me the service fee. I am seriously concerned because I drive this car with my child and I am reading that this is a bad sign and that the breaks might fail at any time. Since the dashboard doesn't give me a warning sign and the dealership says there's no problems based on their diagnostics, even if everyone can hear the actuator go off ever 12 seconds I guess I can safely drive this vehicle. . . It seems like driving a ticking disaster waiting to happen.

Abs pump and master cylinder malfunction. Pump is running very often. Hard braking makes it sound abnormally.

My Prius, along with the thousands of others this has apparently happened to according to a quick online search, has had the c1391 code appear, indicating a failed brake actuator and accumulator. It, like the thousands of Priuses from this generation, have had these faulty brake pump systems develop a leak and begin to fail. You will hear a whirring and hissing noise constantly when it starts going out, eventually resulting in a christmas tree of dash warning lights and reduced braking due to a failsafe kicking on. Toyota apparently issued a "customer service bulletin" that is now ineffective as it only covered if you had the system fail within 10 years of manufactor or 150,000 miles and had the codes appear. Most people's Priuses go out after this, unless you're driving it like you stole it. It is a hefty repair too, being quoted at over $3000 at the Toyota stealsrship!! I have since gone to an independent mechanic and had one portion replaced in hopes that would fix the issue, but it turns out both the actuator and accumulator are needed to be replaced, which is extremely expensive, more so for the actuator than the accumulator, but still exorbitantly expensive. In conjunction with this, Toyota further added difficulties by making their paet numbers they have listed different from the mark number engraved on the part, so buying third party is made a bigger hassle by this as they will not know for certain the part number. This is a huge safety concern as this affects the vehicle's ability to brake. Their service bulletin was the equivalent of offering people bandaids years before they'd be anywhere to getting a cut!! please investigate and please please please lead to Toyota issuing an actual recall, regardless of miles or year from manufacture. More and more Priuses are reaching the time where this will occur and it's a huge safety concern, if not an environmental concern when people start disposing of Priuses due to this massive failure with hefty repair bills.

Brakes failed.

Subject: safety complaint – 2012 Toyota Prius brake booster failure (c1391 code) I am writing to formally report a serious safety defect in my 2012 Toyota Prius involving the brake system. Recently, my vehicle’s dashboard displayed the abs, traction control, and brake warning lights, indicating a critical braking issue. Upon diagnostic testing at a Toyota dealership, the vehicle was found to have dtc code c1391 – brake booster leak/accumulator failure. I later discovered that Toyota acknowledged this defect and issued a customer support program (csp) to cover repairs. However, I was never notified, despite always servicing my vehicle at Toyota dealerships. When I contacted Toyota, they confirmed that my vehicle has been flagged in their system, yet I was never received anything in the mail about the potential brake failure. Toyota initially set the csp expiration in 2023, later extending it to may 2025, but they have refused to repair my vehicle under this program. The estimated repair cost is $4,680. 09 along with a diagnostic fee of 206. 09, which is a significant financial burden for an issue stemming from a known manufacturing defect. Most importantly, this is a major safety hazard: my brakes now produce a loud hissing sound when pressed, indicating imminent failure. If the brake booster fails completely, it could result in a loss of braking power, endangering myself, passengers, and others on the road. Numerous Prius owners have reported similar failures, yet Toyota has not issued a formal recall. I urge NHTSA to investigate this defect further and push Toyota to issue a full recall instead of a limited support program that many owners were unaware of. Given the life-threatening nature of brake failure, Toyota should not be allowed to limit coverage or deny repairs for a problem they have long recognized. I respectfully request that NHTSA take action to ensure Toyota addresses this safety defect responsibly.

The brakes on this Prius started to make weird noises. Because it is a hybrid, I wasn't sure if it was normal. After searching online, it is a known issue. The car has just under 76,000 miles on it. It might be worth $7000 on a good day. Toyota wants to replace two brake parts, numbered 47050-52020 and 04006-74152 to a tune of $2700. According to a Toyota bulletin, this job should take 2. 3 hours. For that amount of work, my local Toyota shop wants almost $2000 in labor. My car was seen by the local shop (being on an island, it is literally the only Toyota shop that this car can be seen) when the "customer support program" 21te01 was in place and they did nothing. Now, the time window has disappeared, even though we only have half of the maximum number of miles to get the repair. Toyota should be ashamed of themselves.

I accidentally slid out into traffic as my brakes failed as I pulled up to stop at the edge of the parking lot. I was nearly hit driver's side on a pickup. Fortunately, it was able to swerve around me and there was no immediate following vehicle. I was able to pull out and back into a nearby parking lot to address the problem with my brakes. Upon speaking to my mechanic and local Toyota dealership I was informed that the brake booster/accumulator had failed and that this was a known issue on my vehicle. Toyota extended a special warranty on these parts several times but did not notify owners of the safety risk. That warranty coverage has expired for my vehicle. I believe it is an inherent safety risk and they obscured it by covering the parts under this extended warranty. I believe they should be recalled and at the least owners should be warned of the risks. All communications were done over the phone or in person, I have no electronic records. I submitted an identical request on my 2011 Prius by accident, as I used it's VIN when I meant to use the VIN on my 2012 Prius. Regardless, I am now concerned for my safety in both vehicles.

Vehicle has good break pads and rotors. Also the vehicle turn on the abs the break and the slippery lights on. When the car was scanned is show code c1391" which indicates a problem with the brake accumulator within the system, often requiring replacement of the brake booster and accumulator assembly. I can't drive the car and other people with same car on 2011 year has the same issue.

Failure in abs system.

The contact owns a 2012 Toyota Prius v. The contact stated that while driving at an undisclosed speed, the brake master cylinder was constantly cycling. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic to be diagnosed or repaired. Most recently, while the vehicle was turned off, the brake master cylinder was cycling. The contact stated that while the keys were in his hands and standing several feet away from the vehicle, the brakes started cycling. The manufacturer was notified of the failure but offered no assistance. The approximate failure mileage was 140,000.

My wife was driving home and four dashboard error lights illuminated (brakes, abs, slip and a yellow light_) the brakes suddenly "went soft" (in her words), and it freaked her out. I now learn that I need to have the brake master cylinder and a booster pump assembly replaced at a cost of over $4,000. Ouch!.

While driving suddenly the abs and vehicle traction lights came on and the car became very slippery, was unable to stop without an excessive amount of space between the car in front of me and me. While looking at the car, I realized the actuator brake booster pump. I then found multiple websites and forums dedicated to people with the same problem ( brakes suddenly not functioning correctly while driving) with the same model car as I have, and there was a service bulletin that shows Toyota acknowledged there was a problem ( and a fix) but with the date of the bulletin and the date it was to be fixed within, it was near impossible to actually have it fixed. My car has 87,000 miles and the brake system is dangerous.

My brakes almost caused me to crash on Jan 18th. I'm driving down the highway and traffic comes to a complete stop. I started braking but my abs, stability control and brake light come on. When this occurred I had to push the brakes to the floor just to stop. My brakes were very unsafe and unpredictable. I had to drive way below the speed limit to make it home, keeping at least 8 car lengths between me. I inspected the vehicle when I made it home. Their is noise coming from the driver side firewall. Something is consistently turning on and off and a slight click after each cycle, every 5 seconds approximately. I was told that it was my abs pump or brake actuator. This is unacceptable and dangerous to all consumers. The fact there was no warning that occurred in a safer environment. I'm so thankful my kid wasn't driving it. Why isn't this a recall? I don't understand how something this dangerous is not a factor to the consumers. I have researched and found many cases that consumers have had a similar issue. This issue is not like brake pads. Their is a clear warning when its time to change brake pads. I honestly would like to see Toyota to fix this issue.

The brake actuator has failed in this 2012 Prius with 135,000 miles. No issues were noticed while braking, however, when starting the car, the abs, brake and traction control warning lights lit up. The Toyota dealership said this is a failed brake actuator and quoted $3,800. We have learned there is a secondary warranty on this part due to constant failures that Toyota issued, however, this warranty only applies to Prius up to 150,000 miles or 10 years from initial use, whichever comes first. This is unfair to most Prius users as this is a common problem happening, but typically happening after the 10 year mark.

Anti lock brake malfunction. Code c1391 leak in brake accumulator. This seems to be a common code for brake issues with Prius. The cost to repair is significant, more than the value of the car. This is a certain safety issue that needs to be addressed. This is clearly a hazzard and will cost lives to those who cannot afford the cost of repair.

Brake booster pump assembly. Toyota has sent a notice of extended warranty for this vehicle which has expired. Without repair, the brakes will loose compression and stop working.

My abs actuator failed. Turns off the boosted braking and cruise control. This is a known issue in Toyotas and it always happens outside the warranty window. This is putting my safety at risk as the brakes don’t work as they’re supposed to.

Without warning, the abs, traction stability, brake and other lights lit up and I lost braking on the highway. Luckily, I was in very light and narrowly avoided a crash. I was able to get home with far less braking power and no regenerative braking. Since then, I have researched the problem and found that this is an extremely common issue. I can remedy it for ten or twenty minutes by putting the car in diag mode and pumping the brakes, but it will do it again, and again. I need a new accumulator and abs module, and the dealer wants thousands for it. I cannot afford it and it is a known flaw and a safety issue. I take my daughter to school in this car, thankfully it's nearby, but it's terrifying. Our other Prius has no issues, and I understand that Toyota has repaired other cars under a warranty program of which I was never notified.

The abs, brake, and traction control lights all illuminated while driving. I took it into a local shop, the computer scanned "brake accumulator leak". The accumulator is buzzing every 10 seconds and the brake fluid needs topping up. Now there is a brake fluid puddle under the car. The fix is to repair the brake master cylinder and replace the brake booster pump. The car is a 2012 with 110,000 miles. This is a known Toyota Prius vehicle issue but they decline to service it and can the brakes can fail.

Wednesday morning I went to start my car to go to work. I noticed the brake would not go down. It was difficult to press. I was unable to go to work safely. I brought my car to a mechanic where I was informed it was a faulty brake booster. When I researched online, I saw many many other Toyota owners went through the exact same issue. There is no recall but it’s a huge issue and a a safety problem.

Abs pump and actuator failed at 100,000 miles. Traction control, ebrake, abs light came on while driving. Many other stories of Toyota vehicles with the same failure.

I was driving down the interstate with my cruise control on when all of a sudden the cruise control disabled and warning lights came up on my dash board. It still drove fine for several weeks. On Friday December 6th, I was going down the road and had to press the brake slightly for a car turning. When I pressed the brake, the car went into a spin. It spun a couple of rotations. Luckily I was on a wide part of the highway and no oncoming cars were approaching. Toyota had a recall for the same code and parts for the 2010 Prius but did not include the 2012 Prius. They just had an alert which I did not receive because the notice went to the former owner. However, I did take my car in for oil change and diagnostic but they did not tell me that there had been a problem with these parts. They want almost $4,000 to repair it. Why would they not include all vehicles with this same part. If it fail on one, it will fail on another. I think Toyota should make them all good. Please make them issue a recall for all of these parts. I took my car to a mechanic but because of special tools needed, you have to take your car to the dealership for repairs. When I called the dealership, I was told I needed a break booster pump and a brake master cylinder for a total of $3, which is ridiculous on a $7,000 car.

I write to add my voice to the litany of complaints in support of NHTSA investigation dp23005. While on an road trip recently the abs, traction control, and brake warning lights all came on. The brake felt squishy and didn't seem to be functioning as confidently as before. I altered my driving (giving plenty of distance, lowering my speed) so that in the event the brakes quit working I would have an exit strategy. I took it to my independent service center as soon as possible who found the code c1391 and diagnosed the need to replace the master cylinder / booster assembly for several thousand dollars. Of course I must do this in order to remain safe but this is clearly a safety issue that could have been catastrophic. Meanwhile I am out of a car for several weeks until the part arrives and out of at least $2000 as quoted by my mechanic ($1640 for the part). The car only has 146,500 miles on it so otherwise would have plenty of life left in it. I'm filing this complaint to add my voice to the open petition and toward the NHTSA's investigation in strong support of holding Toyota responsible for preventing injury and death through a proper recall, as well as against burdening the car owner with the costs of making up for Toyota's negligence on this issue. At the least they need to cover the cost of these necessary safety repairs when they are warned by the lights and reinstate their warranty extension for this issue.

I write to add my voice to the litany of complaints in support of NHTSA investigation dp23005. While on an interstate road trip recently the abs, traction control, and brake warning lights all came on. The brake felt squishy and didn't seem to be functioning as confidently as before. I altered my driving (giving plenty of distance, lowering my speed) so that in the event the brakes quit working I would have an exit strategy. I took it to my independent service center as soon as possible who found the code c1391 and diagnosed the need to replace the master cylinder / booster assembly for several thousand dollars. Of course I must do this in order to remain safe but this is clearly a safety issue that could have been catastrophic. Meanwhile I am out of a car for several weeks until the part arrives and out of at least $2000 as quoted by my mechanic ($1640 for the part). The car only has 146,500 miles on it so otherwise would have plenty of life left in it. I'm filing this complaint to add my voice to the open petition and toward the NHTSA's investigation in strong support of holding Toyota responsible for preventing injury and death through a proper recall, as well as against burdening the car owner with the costs of making up for Toyota's negligence on this issue. At the least they need to cover the cost of these necessary safety repairs when they are warned by the lights and reinstate their warranty extension for this issue ("pol18-03") which expired for my vehicle in August of 2021.

The Toyota Prius of this generation has a known defect in the brake booster pump assembly. About 2 weeks ago the dash lights came on for abs, traction control, general warning light. The brakes work but feel soft, and a motor sound pulses behind the steering column every 8-10 seconds. My mechanic pointed out it is a known problem where the abs booster pump has a faulty valve that doesn’t allow proper pressure to build to engage abs system. I cannot afford the repair: $3890 for master cylinder and brake booster. My concern is that most people can’t afford this repair and without a functioning abs system, people are put at risk from this generation of Prius. Toyota did offer a customer service program acknowledging the issue, but that program only helped if these issues occurred before 2022. With the known issue, why wasn’t a recall required? Toyota should be required to address this safety issue. How many of these Prius are on the road where customers are expected to perform a $4,000. Repair to keep up the safety standards. The car is available for inspection upon request. Thank you.

As I was driving, my breaks suddenly became spongey and unresponsive. I could hear a "hiss" sound come from below me. Abs and other warning lights came on on my dash. As I was near my auto mechanic I tried to make it there safely, and as I drove the brakes seemed to become softer and softer. By the time I had reached my mechanic I was so uncomfortable with its ineffectivness I felt it necessary to use the emergency brake to come to a complete stop. My mechanic confirmed that the issues included the failing of the brake booster, brake master cylinder, accumulator pump, abs, abs computer. According to him this was caused by a set of issues involving internal leaks in the brake booster assembly. These issues were replicatable, and my mechanic says they pose a saftey risk. Even after he gave it a "temporary patch job. " due to this the only times it has been driven were to get it home, to move it along our street so as to not get ticketed for having a stationary vehicle too many days in a row, and one time it was taken up the nearest rise in preparation for a tsunami warning. When looking for replacment parts, my mechanic allerted me to a technical service bulletin that should have been sent out to owners warning them of this issue and offering replacment parts. I never received this notice as I am the second owner of this vehicle, the notices were sent before I owned it, the previous owner claims not to have been aware of this issue herself, and because it was a voluntary service call, when researching the vehicle myself for any reported issues such as recalls, none had come up, meaning I had no way of knowing. To add to this, I contacted Toyota to see if they would honor the past offer to service this issue, but Toyota refuses to replace the parts now as it is too far past the voluntary service dates they set.

Have suddenly brake failture, w code c1391, it problem persist car do not stop by pressing brake , it is too dangerous to drive this car!!!! what you can help me w this recall or rebate option for brake repair?.

2012 Prius in very good condition with 180k miles- only 12 years old. Driving on back roads (thankfully) and the drivers side rear wheel compelely fell off while driving. I was doing about 30 mph and felt like there was a flat tire so I was in the process of pulling over when the whole rear assembly snapped. The wheel hit the rear quarter of the car and bounced about 100 feet down the road. I could have been on the highway and this could have been fatal I believe. Very, very scary. As can be seen in attached photos the issue was rust from the inside. This is very concerning since there was no way for me to know this was an issue. I could have been killed or killed someone else. I believe Toyota needs to look into this since there are other Prius' out there the same thing happened to on this very thread. Although this is a massachusetts car I have owed it since 25k miles and have maintained it impeccably. I always have the undercarriage cleaned after driving on salty roads. Safety inspection was current- only done the month before. Had that wheel bearing replaced about 2 weeks before the incident and the reputable mechanic reported no issues. There was no warning except for maybe a minute before it happened- the car was vibrating like I had a flat tire. The damage repair estimate on this was $8500. Catastrophic fail Toyota. Is this a rust issue like the tacoma, tundra, and sequoia?????.

I was driving and all of a sudden the emergency brake light, the abs brake light and a couple more turned on and I had no more brakes. I had just driven 25 miles with it and stopped at many red lights along the way with no issue and no warning lights. I could have gotten into a major accident if it had happened anywhere else in my route. Fortunately, I was about a mile from my house and the hybrid motor helped slow the car down. I was unable to stop at any stop sign in my development and here again was very fortunate that there were no cars along the way. Once I got home, I got it towed to Toyota and was told it is an internal failure of the actuator. I contacted Toyota America and was just told that there was a campaign to repair this but that I had passed the date. My car has only been serviced at the same Toyota in my city since I got it. I religiously brought it every 5000 miles. I am shocked that they never mentioned this campaign to me and that they didn't initiate a repair during the campaign. This is a major issue that needs to be addressed and Toyota needs to be held accountable.

1. The abs system failed upon inspection at a dealership. Specifically the abs accumulator and booster. 2. The abs system put us at risk by failing prematurely, and traction control and abs functions seemingly stopped working while driving on the road. 3. Yes, dealership confirmed the issue with a full diagnostic, and the part has a customer support program bulletin/TSB out for this specific issue. 4. Inspected by manufacturer dealership service center. 5. Lights such as the parking brake, abs, and (!) lit up while driving and the failure occurred at the same time.

Jtdzn3eu1c3157707 brake master cylinder and brake booster pump assemblies both failed. Replaced with used parts from an identical part number from another jtdzn3euxc3030566 2012 Prius. Now code c1391 the parts from the donor vehicle have failed. Identical failure.

Brake master cylinder and brake booster accumulator assemblies brake parts from this vehicle failed on another vehicle.

About three weeks ago, my daughter told me that several lights were on on her display. I checked and among them were the traction control and 2 other related to the brake system. I looked up possible causes on the internet and it seemed the brake booster/master cylinder could be a culprit, but then I checked the fluid reservoir and the fluid was low, so I topped it off, drove the car, pumped the brakes a few times and all the lights went off. About a week later the lights were back on. I checked all the lines and saw not visible signs of leaks and decided to take it to a mechanic. I took it to a local mechanic and I was told that the brake master cylinder with brake booster failed and had to be replaced. Afterward the brakes were repaired I went to 2 local Toyota dealerships to check the price of the parts. The first dealership provided the prices without any discussion. At the second dealership, the employee who waited on me, after I provided her the VIN and told her that I need the price of the brake booster/master cylinder,m told me that there was a service notice on the booster/master cylinder because of a high rate of failure and that I would have to check with the service department before she could sell me the part. This is concerning, if Toyota knew/knows that the part has a high rate of failure, why wasn't a recall notice issued?.

After starting the car on 7/30/24, the brake system warning light, abs,slip indicator, and master warning light all came on indicating an issue with the brake system. We were able to get it to the local dealership and when they ran diagnostics on it, it returned a code c1391, which confirmed the issue. This was addressed in 2020 by Toyota, but only for cars 10 years or 150,000 miles old. Our car is a 2022 with 105,000 miles on it, but we are outside of the year limit (car was 8 years old when the customer service program was released).