2015 Toyota Prius: brake failure

Filed Sep 17, 2026 · Brakes · CA

I am reporting an active, severe safety hazard regarding the braking system on my 2015 Toyota Prius ( Mileage: 79,000). The vehicle has been officially diagnosed by Toyota Culver City with Diagnostic Trouble Code DTC C1391, confirming an internal failure and lack of pressure within the brake booster/actuator assembly. This component defect causes an immediate compromise to the vehicle's braking efficiency and hydraulic pressure, causing a sudden loss of braking power and significantly increasing stopping distances.Toyota was fully aware of this dangerous defect and initiated Customer Support Program ZJB to address it. However, Toyota Brand Engagement Center (Case #260909002032) has explicitly admitted via recorded voicemail that they mailed the safety/defect notification only to a previous owner and failed to notify me. Because they did not cross-reference current registration data, I was never notified of the defect and was deprived of a preemptive remedy before their arbitrary 10-year calendar clock expired. At only 79,000 miles, this critical safety component has failed prematurely, creating an active hazard on public roads. Toyota is refusing to cover the $3,890 repair despite their documented failure to notify the current owner.

Filed Aug 11, 2026 · Brakes, Driver assistance · CA

Code DTC C1391 - Abnormal leak of accumulator pressure. Internal failure of the brake booster pump assembly, preventing the system from maintaining proper hydraulic pressure. This means the brakes don't work, putting the driver's and passengers' lives at risk. This DTC C1391 code and problem were reproduced and confirmed by an independent service center who specializes in 3rd generation priuses. There were warning lights that lit up when the brakes failed - the ABS, traction control, and brake light all lit up but only after the brakes had stopped working. This is a known manufacturer defect but toyota won't pay to fix it because they put a 10 year limit on first driven date or 150,000 miles. This prius only has 100k miles but toyota still won't stand behind their product even though they have admitted it was a manufacturing defect and they sold a defective product.

Filed Jul 15, 2026 · Electrical, Engine · CA · crash

Pulling out of a parking stall, when put vehicle in drive, the engine revved up and accelerated - vehicle crashed, the brakes did not work- there was skid marks. Floor mats are factory OEM were installed properly. I did not hit the accelerator and I am in good health and mind. I have driving for over 30 years, never had and accident nor a ticket! - A county officer was at the seen and left me with vehicle that had to be towed away. The Vehicle is a total loss. I have insurance but felt that this incident need to be reported, There is no safety recalls and the vehicle was always property maintained

Filed May 6, 2026 · Brakes · CA

On 4/16/26, while driving my 2015 Toyota Prius (approximately 87,000 miles) on the freeway, I applied the brakes while transitioning from the [XXX] onto the [XXX] . As I veered right on the curved onramp, the brakes failed to engage properly, causing the vehicle to spin out of control and collide with the side railing. There were fortunately no nearby vehicles on the 2-lane onramp at the time. Under slightly different circumstances, this incident could easily have resulted in serious injury or death to myself and/or others. No airbags deployed. Although I was physically unharmed, I was extremely shaken by the incident. Immediately after the collision, the brake warning light, ABS warning light, and another warning indicator illuminated on the dashboard. Prior to the incident, I had not experienced braking problems severe enough to suggest imminent failure. On 4/17/26, I brought the vehicle to Toyota of Cerritos for diagnostic evaluation. I was informed that the brake booster was the issue and that the vehicle was unsafe to drive. The vehicle was towed to a collision repair center affiliated with my insurance company. After repairing the external collision damage, the collision center informed me that the brake booster malfunction that caused the incident could not be repaired there and would require dealership service. External repair alone: $3706, in addition to increased automobile insurance premiums expected over the next 3 years. I also contacted Toyota Motor Corporation regarding Customer Support Program coverage related to brake booster issues and was informed that the program expired in 2025 and no assistance would be provided. I am submitting this report because this brake booster malfunction created a serious and unexpected safety hazard resulting in loss of vehicle control on a freeway interchange. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jan 12, 2026 · Brakes, Driver assistance · TX

While driving, my brakes became mushy and ineffective. Brake warning lights came on, also. It was very scary driving in rush hour traffic with little to no brakes. There was no reliability. Just keeping as much as possible space between cars, using Hazard lights &prayer.

Filed Sep 22, 2025 · Brakes, Electrical · CA

Got the warning code for C1391 for the brake booster. It failed at 140k miles but because it failed past the 10 year mark did not qualify for the Toyota extended warranty program. I don't think the warranty program is good enough and should be addressed as a recall. I had sudden total brake failure on the highway which could have been extremely deadly.

Filed Sep 19, 2025 · Brakes · 186,000 miles · OK

The contact owns a 2015 Toyota Prius. The contact stated that while driving at various speeds and depressing the brake pedal, the brake pedal went to the floorboard, and the vehicle hesitated while responding. The traction control, ABS, BRAKES, and cruise control warning lights were illuminated. The vehicle was taken to Gasket Masters Inc, where it was diagnosed and determined that the ABS assembly was leaking fluid into the braking system, and the ABS module had failed, causing the brake pump to fail. The vehicle was not repaired. Additionally, the malfunction warning light was illuminated. The vehicle was taken to the dealer, but was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 186,000.

Filed Jul 2, 2025 · Brakes · AL

omponent/System Involved: SERVICE BRAKES, HYDRAULIC ⸻ Make: Toyota Model: Prius Year: 2015 Mileage: 155,470 VIN: [XXX] ⸻ What happened: My 2015 Toyota Prius is experiencing brake failure symptoms related to a known defect addressed in Toyota’s Warranty Enhancement Program ZJB. The vehicle has triggered DTC codes C1256 and C1391, which indicate failure of the brake booster and master cylinder — a problem widely reported by Prius owners. The defect causes decreased brake effectiveness and increased stopping distance. My Prius is just 5,470 miles over Toyota’s 150,000-mile coverage cap, and despite confirming the exact codes, the dealership refused to repair unless Toyota pays first. Toyota Corporate opened Case #[XXX], but has not offered a resolution. This is a safety-critical issue that Toyota acknowledges in internal service bulletins, but they are denying assistance based on a technicality, despite my vehicle having the exact failure their program is designed to address. I am filing this complaint because I believe Toyota is avoiding responsibility for a dangerous manufacturing defect affecting braking performance and safety. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Apr 26, 2025 · Brakes · GA

Car feels like it lunges forward while braking over bumps. I have learned this is a known manufacture defect with the Brake Booster and Brake Actuator which Toyota is refusing to replace outside of 10 years from manufacture date. This is a critical safety item and failure can result in loss of brake power. Most owners do not know this part even exists until failure has happened already.

Filed Apr 26, 2023 · Brakes · TX

1. Brake accumulator pump is running too often, indicating that there is a pressure leak in the braking system. 2. As designed the pump will run only on occasion to charge the booster fully. This pump runs a lot, whether the car is running, or not, whether the brakes are applied, or not, and regardless of braking rigorously or gently. 3. Occasionally, on start up, brake pedal goes to the floor as the accumulator has lost all charge. 3. No brake warning lights on dash, yet. 4. No service codes known, yet. Toyota had a customer support program to address this issue, extending warranty to 10 years or 150,000 miles. I am at 160,000, 8 years. The problem has been occurring for a while, but I was not aware as it was my wife's car and driven solely by her. I was told today by a Toyota resolution specialist that no help would be forthcoming, and to hope that the federal safety agency issues a recall wherein my problem with the braking system would then be addressed. This seems problematic for many reasons, not the least of which is that it is regarding BRAKES, an integral part of the safety equipment to ensure our highways are without danger or have no known issues that have not been resolved by a car manufacturer. My Toyota case number is 230426001055. This 'complaint' is to alert this agency that there is a problem with my vehicle, and others, known by Toyota, as evidenced by past Customer Support Program, and as substantiated today by service rep at Family Toyota of Burleson, and there is no recompense available for the $3,000.00 repair required to ensure my vehicle safely travels our nations highways. While I understand that a car cannot be warrantied indefinitely, an eight year old car that has been meticulously maintained with a serious safety time bomb should not fall upon the owner entirely, nor should it be the responsibility of your agency to force the hand of the automaker. Since that is there stance, I appeal to you to respond seriously and help me try to remedy.

Filed Feb 7, 2023 · Brakes · 188,000 miles · FL

The brake assist. Driving and suddenly no brakes. Happened 2x in this vehicle and had to get a tow each time, even after getting new brake pads the first time it happened at my mechanics. The dealer confirmed today that they would fix the problem at $2700. The lights for traction and abs went off with a warning sound. Pulled over both times and called aaa for tow…..each a separate incident.

Filed Jun 6, 2022 · Brakes · 80,000 miles · IL · crash

The contact owns a 2015 Toyota Prius. The contact stated that as he approached a stop light at 25 MPH, the brake pedal was depressed and traveled to the floorboard as he attempted to stop the vehicle. The brakes failed to operate without warning as he hit the vehicle in front of him. The air bags did not deploy upon impact. A police report was filed and both the contact and the other driver were able to drive away from the scene. No injuries were reported. Prior to this failure, the contact stated that the same failure occurred months prior while traveling at 20 MPH in the rain. The contact stated that the brakes failed to operate without warning as he depressed the brake pedal to the floorboard; he hit an unknown object on the road due to the failure. The contact initially thought that the failure was related to slippery roadways; however, after the most recent failure, he related the prior incident with his most recent failure. The dealer nor the manufacturer had yet to be notified of the failure. The vehicle had yet to be serviced or diagnosed. The failure mileage was approximately 80,000.