What 186 owners told NHTSA about the 2014 Toyota Prius Plug-in Hybrid

My 2014 Toyota Prius (VIN [XXX] , 77,000 miles) displayed Brake, ABS, and Slip warning lights. A mechanic confirmed failure of the Brake Booster and Pump Assembly (DTC C1391). Toyota previously acknowledged this as a safety-related defect under Customer Support Program ZJB, but my coverage expired because I never received Toyota’s notice dated May 21, 2019. My car has been undrivable for weeks and Toyota refuses goodwill repair. This is a serious brake safety issue that should be reviewed for recall or extended coverage since many Prius owners have experienced the same failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11696950

There was a safety recall issued for brake system malfunctions involving the brake booster and brake booster pump assemblies on my vehicle. Unfortunately, the recall expired on December 31, 2024. On March 4, 2025, at 4:10 PM, I contacted the District Manager Advocate in Plano, Texas. I explained that I had been in the ICU twice and am now [XXX]. During the recall period, I was in and out of hospitals for more than four years, making it impossible for me to be aware of or respond to the recall in time. My vehicle has since begun exhibiting the exact symptoms outlined in the recall. When I brought this to their attention, I was told that while the issue was indeed covered under a past recall, there is nothing they can do now because it has expired. This vehicle is our only mode of transportation, which is critical for my ongoing medical treatments, as well as for my husband who recently suffered a heart attack. As I write this, we have no other option but to continue using the vehicle—despite the serious safety risk—because of the urgent and necessary care both of us require. On August 4, 2025, I contacted Toyota headquarters. They reached out to the dealership and spoke with management, but unfortunately, no resolution was offered except for information about a separate, newer recall. I followed up again with the District Manager and spoke with Ashley, who informed me that after escalating the case, there was still nothing further they could do and she expressed her apologies. This situation has caused further deterioration to my health due to the stress and anxiety of potential vehicle failure, and it has added to the burden of my husband’s fragile health condition. At this time, he has been unable to return to work, and we have no income to cover the cost of a repair that should have been addressed through the original recall. We would deeply appreciate any assistance, reconsideration, or compassionate review of our case. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11678383

I am writing to express my profound concern and disappointment regarding a recent, terrifying incident involving the brake system of my 2014 Toyota Prius. On Saturday, June 21, 2025, while driving with other passengers, my vehicle experienced a complete and sudden brake failure. Multiple warning lights illuminated on the dashboard, and despite my efforts, the brakes became unresponsive, making it impossible to stop the car. The sheer terror and helplessness I felt in that moment, with the very real potential for a catastrophic accident involving myself, my passengers, and other road users, is indescribable. Fortunately, through sheer luck and quick thinking, I was able to make an emergency stop on the side of the road, preventing any collision or injury. However, the emotional toll of that experience, the lingering stress, and the fear of a recurrence remain significant. I was subsequently informed that the cause of the failure was a leak in the brake accumulator. I am attaching the diagnosis and repair invoice. The necessary repairs were not completed until Wednesday, June 25th. This unforeseen and critical malfunction also necessitated the expense of a rental car for four days, adding to the financial burden and inconvenience. My frustration is compounded by the fact that this brake accumulator issue is a well-documented and known defect in Toyota Prius models, specifically affecting 2010-2015 vehicles. Toyota itself has previously issued a Technical Service Bulletin (TSB T-SB-0043-13) acknowledging this problem and offering warranty extensions for affected vehicles, typically up to 10 years or 150,000 miles. Despite this being a recognized safety concern, I was informed that my vehicle falls approximately eight months outside the 10-year warranty period, thus disqualifying me.

NHTSA ODI 11671120

After 120K miles and 11 years of use, my Prius 3 brake booster pump failed while I was driving. The warning lights came on, including the ABS and brake lights. My brake felt strange, and I had to finish my drive to the dealership keeping a large driving distance so the brakes would work in time. I was advised that this was a result of a C1391 error and that the brake pump part is only covered under extended warranty for 10 years. The advisors at the dealership said it is extremely common for cars to come in with this problem just after the warranty period has ended. I have spoken to other Prius user who have complained of the same issue and are considering a class action lawsuit because this safety issue is so common.

NHTSA ODI 11662237

While driving my dashboard lit up with Brake, ABS, and traction control warning lights. Brake pedal fell to the floor when pressed. I was then able to stop the car. I brought the car to a local auto parts store, where they were able to determine that the error code was C1391 brake accumulator pressure leak. I made an appointment and brought my car to my local Toyota dealer the next day. I was informed that the brake booster assembly, brake booster pump, and master cylinder would have to be replaced, at a cost of approximately $4035.00. I was informed that Toyota issued a Customer Satisfaction Program for this exact issue on my car. While my car has 129,000 miles and falls within their coverage range of 150,000, the car’s age of 11 years did not fall within their limit of 10 years. According to Toyota, this is a known failure and my only problem is that my brakes did not fail sooner. Toyota’s corporate office denied my appeal to cover the cost of the repair. The local Toyota dealer charged me $150 to read the code and confirm what the local Auto parts store was able to do for free.

NHTSA ODI 11659668

Issue started with a noise sounding like a motor constantly trying to prime its self. Then while driving on freeway ABS light Brake light and traction control lights all came on. Took car to dealership and was given a $3700 bill to replace Brake Booster Master Cylinder and Brake booster pump. This is a known issue to Toyota and have offered an extended warranty 10 years or 150000 miles but not a recall. My vehicle is at 11 years and 123000 miles. This issue put my family in danger due to the threat of total brake failure.

NHTSA ODI 11657656

Was driving down the road and the brakes stopped working and the the brake light the traction light and abs light came on. The brakes only worked if i put the pedal all the way to the floor after that. I checked online and found numerous other people have had this issue but no recall has ever been done. only nhtsa safety notices and a volunteered customer support program by toyota which was no longer being honored because I was passed the 10 year mark even though my vehicle was still under the 150k mile threshold by toyota. I wish your organization would force toyota to do a full recall on this. this is a dangerous safety issue involving a defective brake booster and master cylinder

NHTSA ODI 11655290

The contact owns a 2014 Toyota Prius. The contact stated while driving at an undisclosed speed, the vehicle failed to stop or decelerate as intended while the brake pedal was depressed. The ABS and service brake warning lights were illuminated. The contact added brake fluid; however, the failure persisted. The vehicle was taken to a local dealer where it was diagnosed; however, the cause of the failure was not yet determined. The vehicle was taken to a local Auto Zone, where it was scanned with an OBD2 scanner and DTC: C1391; was retrieved. The vehicle was not repaired. The manufacturer was notified of the failure and the contact was informed that the failure was related to an unidentified Toyota Campaign; however, the warranty had expired. The failure mileage was approximately 92,802.

NHTSA ODI 11653168

The brake booster assist assembly failed, causing a leak of brake fluid, im told that over time this failure can lead to a break failure. I contacted Toyota. They informed me that there was an assistance program for fixing this defect. However it expired in 2024? If they know about a defect why did the program expire? This is a safety issue.

NHTSA ODI 11652740

Failed Brake booster and pump assembly, confirmed by Toyota service. Warning lights turned on all at once: AEB, skid control and brake light. Estimated cost to repair is $3,000.

NHTSA ODI 11649889

The brake booster assembly failed at odometer reading 92,463. Prior to diagnosis, several dashboard lights turned on, and the vehicle's braking was negatively affected. The failed brake booster assembly problem was diagnosed, confirmed and repaired by an ASE certified repair technician on 3/14/2024. Toyota refuses to reimburse me for this expensive repair ($2,375.97.) Toyota has operated in an unethical way by not issuing a true RECALL for this known defect. Its "Customer Support Program Bulletin" is full of unclear instructions and vague definitions of what is required for reimbursement. Toyota refuses to reimburse me for even a portion of this expensive repair. NTHSB should force Toyota to issue a recall and reimburse all affected customers who incurred this $2,000 - $3,000 repair.

NHTSA ODI 11645631

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NHTSA ODI 11644177

Brake booster system failed and needs replacement. Was told that there was a recall but it expired in 2024 and my car is not covered. Cal has 102000 miles on it.

NHTSA ODI 11641282

Failed brake booster on 2014 Toyota Prius due to Customer Support Program Bulletin POL18-03 See attached documents sent to Toyota. They would not reimburse the ~ $3,000 repair to the brake booster which was in the Customer Support Program Bulletin POL18-03 Almost had an accident and the repair was done within the repair window.

NHTSA ODI 11641038

Got code C1391, a common issue with the Prius. Brake Booster Assembly is defective due in no part to owner/driver of vehicle. This creates a serious safety issue with braking. Traction control light, brake light, and ABC light are all on and repair is ridiculously expensive.

NHTSA ODI 11635057

The contact owns a 2014 Toyota Prius Plug-In-Hybrid. The contact stated while driving 65 MPH, the brake pedal was depressed; however, the vehicle failed to stop as intended. The contact stated that the brake pedal had to be depressed abnormally hard to stop the vehicle. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure. The contact was informed that the VIN was not under recall. The failure mileage was unknown.

NHTSA ODI 11631073

I started noticing the ghosting or tripling of light issue in my windshield. I mostly noticed this during night times, I initially thought I was just tired and my eyes were tired, but I’ve been able to photograph it and verify my experience with other people. This effect is horrible for my eyesight and makes all lights at night so blurry I cannot drive safely.

NHTSA ODI 11631087

Apparently there is a known defect on the brake actuator/master cylinder/booster on the 2014 Prius that would have been addressed if the car had been driven for less than 10 years or 150,000 miles. We purchased our car in April 2014 and the part just failed yesterday at only 126,000 miles. We understand that there is a pending class action suit (or perhaps one that was settled) but do not know how to become a member of it. It seems as if they knew that the part was defective, but did not offer to do a voluntary recall and remediate this before a failure, they should have, but instead, now we have a $3400 repair bill. Requesting assistance in evaluating whether there was negligence and or liability for them not addressing this issue in a timely manner.

NHTSA ODI 11630728

Yesterday, while driving on the interstate, all of the brake related warning lights on my dashboard lit up- ABS, traction control, brake, caution)- causing me concern, so I looked for the next exit. While exiting and slowing, I noticed my brakes felt different and were not as responsive as usual. I called my mechanic and cautiously headed to his shop a couple of miles away. Today, I met with him and found out that there is a leak in the brake booster line, but the extent of the problem is yet to be determined. I immediately did an internet search for my model year and found that there was a safety campaign on other Toyota hybrids for that year, so I called the Toyota customer service number. I was told that my vehicle had an extended warranty for the brake booster, but it expired 9 months prior, 10 years post purchase, The rep has escalated my issue but I will have to wait to see if someone with more authority can potentially give me an additional extension. Meanwhile, my car is not drivable, as the brakes could fail at any moment. In my estimation, this should not be a time limited coverage, but an actual recall covered by Toyota. This is not normal brake pad rotor wear and tear, but a known issue with the assembly system and a true safety hazard that one cannot foresee without experiencing minor to catastrophic failure of the system.

NHTSA ODI 11627019

The brake master cylinder and brake booster failed. It is available for inspection upon request. My safety was put at risk as braking distance increased significantly. The problem has not yet been confirmed by a dealer or independent service center. The vehicle has not yet been inspected. The warning lights appeared upon failure. Brake warning light, traction control light, and ABS light appeared. Prior to complete failure, the brake booster would cycle on after opening the door and would then cycle every few seconds for 10 minutes or so after parking.

NHTSA ODI 11625824

I WENT TO SEVERAL MECHANICS AND GOT THE SAME ISSUE CONFIRMED. IT IS A BOOSTER BRAKE SYSTEM ISSUE. I CALLED CONSUMER ADVOCATES AND THEY SAID THE NOTICE WENT OUT IN 2019 AND SINCE THEN EXPIRED. THEREFORE DEALERSHIP IS NOT GOING TO REPAIR THE DEFECT. I RECEIVED NO SUCH NOTICE. WHEN I CONTENDED THAT THIS IS A SAFETY ISSUE AND SHOULD IMMEDIATELY BE HANDLED AND MY CAR HAS 80,000 MILES ON IT AND IT HAS NOT EVEN BEEN 10 YEARS THEY REFUSED. FROM MY RESEARCH I SEE THAT IT IS A WIDE SPREAD ISSUE WITH THE BREAK BOOSTER AND DEFFINATELY WARRANTS A RECALL. I AM DISABLED AND HAVE MANY MEDICAL ISSUES I NEED MONEY FOR AND CAN NOT AFFORD $3000 MANUFACTURING FAULT DEFECT IS NOT MY RESPONSIBILITY.

NHTSA ODI 11625528

Something felt wrong with the brakes for many years, but mechanics checked the brake pads and rotors and said they were fine on multiple service visits. I had multiple close calls during quick stops on highways, I though I just needed new tires. I then started to hear a whirring buzz noise become more and more frequent. I researched what it was and found on reddit that there was customer support program ZJB to repair failed brake accumulators, which affects hundreds of thousands of these cars. The problem was that my brakes were only in the process of failing rather than being fully failed enough to send codes and light up the dashboard, which is the only way the customer support program would cover the $4,000 repair. The failure finally happened when I was three hours from home and had half the braking power as usual and had to limp the car home for fear of the brakes going completely out. I can't believe Toyota is letting this many people drive around with a potentially catastrophic brake issue.

NHTSA ODI 11624998

I was driving on the highway during rush hour when a loud beeping noice began. My 15 year old cousin was in the passenger seat and began to check for the source of the beeping. I was driving 55mph on a busy highway with no safe shoulder stop. As I was preparing for the exit, the brakes suddenly became dysfunctional. The pedal was extremely hard to press down and I found myself unable to slow down the car in enough time to avoid hitting upcoming traffic. I found myself in an urgent, life threatening situation and needed to pull over into the emergency lane located before the exit. I could not just consider my safety, but that of other drivers and my 15 year old passenger. She is traumatized. I was able to get the car to stop with my entire weight on the pedal. Once stopped, I scrambled to find the reason for the sudden brake problem, checking if anything rolled under my foot, if the floor mat was loose, if the gear shift was wrong, even checked if I accidentally hit the emergency brake. Nothing was out of place. No new dash lights. I looked in the manual. I had no information. I went to jiffy lube and they performed a diagnostic test and informed me they are unable see all the codes with hybrids because Toyota’s computer can only see Just in August I went to Toyota for my oil change, nothing was said about the brakes needing to be fixed and how repairing them now would prevent the failure of the accumulator pump system. If I had known paying $400-$500 for the brakes then would prevent having to pay $3000 to replace a pump. I would have made that sacrifice and went outside of my budget. This is paramount information that should be disclosed to all Toyota customers that take their car in for care and pay. After further research, I STRONGLY BELIEVE TOYOTA EMPLOYEES PURPOSELY WITHHOLD INFORMATION FROM THEIR CUSTOMERS NOT INFORMING CONSUMERS ABOUT AVOIDING PUMP FAILURE AND THE NEED REPAIR THEIR BRAKES AND IS COMPLICIT IN ANY INCIDENT CAUSED BY PUMP FAILURE MAY CAUSE.

NHTSA ODI 11622029

Without warning, my brakes completely stopped working and I was fortunate enough to be somewhere I was able to pull over without being killed. Toyota is aware of this issue, but put a 10 year timeline on the complementary repair, which is totally unacceptable, as owners were not notified directly about this program, therefore how could we know it existed, was a problem, and to go get it fixed within their arbitrary deadline? I could have died losing brakes on the freeway, or even could have killed or injured others. This is a known, and severe safety hazard, and Toyota is not taking responsibility. It is unconscionable. Hoping for a class action lawsuit. It was a $5500 repair in California, which was almost the value of the car. Absolutely brutal and horrendous business practices from this company. Shame on them. I hope this agency NHTSA will add this report to the pile of others who have reported this, and actually take meaningful action for those of us who have been put at risk, and ripped off in the process.

NHTSA ODI 11621414

My 2014 prius experienced a failing brake booster actuator assembly. I was driving when suddenly my traction control light came on and my brake pedal turned mushy. I pulled over to a parking lot and put my vehicle in park. As soon as I did this, the ABS and parking brake light both turned on. I had the vehicle towed to the Toyota dealership. They diagnosed the problem as an internal leak in the brake booster actuator assembly. This is a common problem with these vehicles, but instead of Toyota issuing a recall, they only did an extended warranty coverage of which my prius didn't fit the parameters. Now I am stuck with a vehicle that is unsafe to drive and a repair estimate of $3,900 because of one of their parts failing. This should clearly have been made a recall with the volume of prius owners experiencing this problem. What a disappointment after having 3 Toyotas for many years.

NHTSA ODI 11619899