What 233 owners told NHTSA about the 2014 Toyota Prius Phev

My brakes consistently lock and the car lunges forward. Driving down the highway I tapped my brakes and they didn’t work. I lost traction in the brakes. I had no control over the car or speed. I’m scared everyday I have to drive it. This is extremely dangerous and I've seen this comment often with this vehicle. Toyota said they had an extended warranty for this but it expired. I never received any mail or phone calls stating that this was a known defect. They say they can’t do anything now and are quoting me over $3000 to fix it.

NHTSA ODI 11689489

The brake actuator failed, it can be available for inspection anytime. My ABS light, brake light, and traction control lights all came on to indicate the failure. Since the hybrid engine requires the breaking system to recharge, failure of this part will eventually lead you to be stranded if it isn’t functional. Additionally, the responsiveness of the breaks makes driving at higher speeds a lot riskier. Toyota offered an "extended warranty" to have the parts replaced for free for 10 years or 150,000 miles, whichever came first. My make is 2014, at only 89,000 miles.

NHTSA ODI 11681994

The contact owns a 2014 Toyota Prius. The contact stated that the ABS and the traction control warning lights were illuminated. The vehicle was taken to the dealer to be diagnosed, and the contact was informed that the brake master cylinder needed to be replaced. The vehicle was not repaired. The vehicle was taken to a certified mechanic and was diagnosed, and it was determined that the brake booster had failed and needed to be replaced. The vehicle was repaired; however, one day later, both warning lights returned. The vehicle was returned to the mechanic and air was blown into the hydraulic valves and the other valves were cleaned; however, the failure persisted. The manufacturer was not informed of the failure. The failure mileage was approximately 150,000.

NHTSA ODI 11680048

Apparently Toyota knows of a recurring problem with the brake actuator. I took my Toyota Prius to the dealer for an unrelated recall issue that they repaired and I asked them what the sound was that I kept hearing every 10 seconds or so. The told me it is the brake actuator, but did not seem concerned at all that I get it repaired right away. They did quote me a very high price to have it fixed by them. I have chosen to take it to my mechanic for repair. In the mean time, I decided to research this on the internet and discovered that it is a known problem by Toyota and there is a class action suite filed on them. I want Toyota to pay to have it fixed! I fear for my life and lives of others with the same issue.

NHTSA ODI 11680117

I was told that my Brake Booster and Brake Booster Pump Assembly needed replaced. I had specifically asked my dealership in the past if there were any issues with my car and was told that there was nothing, which was untrue. I called Toyota and was told that I was mailed something back in 2018, but I do not remember receiving it. Now I am told that this has expired. I wanted to know if I had any recourse or extension time on this program 21 TE01. I am afraid that my brakes will not work, as the lights go off and on. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11679204

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

Cruise Control Not Working. Traction Control Light Active, Brake Light Active, And Light Active The cause was diagnosed by Toyota of Paris. TSB for C1391 Code abnormal leak in accumulator. The corrective action is to replace brake booster assembly with Master cylinder and Brake Booster pump Assembly.

NHTSA ODI 11673351

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

See Attached Letter

NHTSA ODI 11670687

We were driving on a city street about 25-30mph and the car jerked suddenly and the lights on the dashboard illuminated and the "Check Hybrid System" message came up as well. The car was able to coast to a nearby parking lot. We attempted to drive the car home and the car stalled in the middle of the street. We were able to push the car off the road and then get it towed. The presented a potentially very dangerous situation as the car had a complete failure while driving in the middle of the road. The Toyota service department ran a diagnosis which returned DTC P0A94. All of this indicates that the car should be covered under the CUSTOMER CONFIDENCE PROGRAM 23TE03 however that program seems to only cover the 2010-2015 Prius and 2011-2017 Prius V models and not the Prius C. There are several reports of this same issue happening on the Prius C as well though so it doesn't make sense that it is not covered.

NHTSA ODI 11667479

2014 Toyota Prius C with 220k miles. Four warning lights came on while driving. Brakes became not responsive unless you press down very hard. Regenerative braking, went away. The Brake pump can be audibly heard turning on every few seconds.

NHTSA ODI 11665317

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

My 2014 Toyota Prius C experienced a complete hybrid inverter failure. The part number of the inverter is the same as the one covered under Toyota’s inverter recalls (such as Recall J0V), yet my VIN is not included. The failure created a serious safety concern, as the vehicle lost power while in motion. Toyota’s recall appears to be too limited in scope and may need to be expanded to cover Prius C models that share the same faulty part. I am requesting that NHTSA investigate this issue, as it appears to involve the same hardware defect acknowledged in other Prius models.

NHTSA ODI 11659113

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

Code C1391 Master cylinder/ break booster

NHTSA ODI 11649719

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