Toyota Prius brake failure problems

Filed Oct 16, 2026 · Brakes · TX

My vehicle is experiencing the well-known brake booster failure. This started at 90,000 miles, with an increased frequency in the running of the brake booster. It has steadily gotten worse, and now the pump runs with every brake application or every 13 seconds. There is now a hissing sound when I apply the brakes. I have repeatedly taken this to Toyota dealers and have been told: "The system is working as designed; no issues found". When I asked why the pump runs so frequently. No response. This is a $4,000 repair that Toyota should step up and fix. The next step in the degradation of this part is a loss of brake pressure. I tried resolving this matter with Toyota Corporate and was denied, even though my mileage is well below the extended coverage for this part of 150K miles and 10 years.

Filed Oct 12, 2026 · Brakes · MD

While driving our 2013 Toyota Prius, the vehicle experienced a sudden and severe loss of braking effectiveness while the vehicle was in motion. This created an immediate safety risk because the vehicle did not respond to braking as expected. After the incident, the vehicle displayed the red BRAKE warning light, ABS warning light, brake-system warning light, and an audible warning. The vehicle was not driven after the failure and was transported to a Toyota dealership for diagnosis. The dealer confirmed a brake-system fault and recorded diagnostic trouble codes C1241, C1252, C1253, and C1256. Toyota previously issued Customer Support Program ZJB for certain 2010–2015 Prius vehicles involving internal brake booster and brake booster pump malfunctions. Toyota’s documentation for that condition identifies C1252, C1253, C1256, and C1391 as relevant diagnostic codes. This vehicle has three of those listed codes. The problem has been confirmed by the Toyota dealership. The failed brake-system components remain installed and are available for inspection at this time. There were no known brake-system warning lamps before the braking failure. The warning lamps and audible alarm appeared in connection with or immediately after the 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 Sep 4, 2026 · Brakes · TX

While driving my 2014 Toyota Prius, the BRAKE, ABS, and vehicle stability/traction control warning lights illuminated. There was no crash, injury, or noticeable loss of braking before the warnings appeared, and there were no preceding symptoms. The vehicle was evaluated by Mac Haik Toyota in League City, TX, an authorized Toyota dealer. They diagnosed DTC C1391, “Abnormal Leak of Accumulator,” and determined that the brake booster and brake booster pump/accumulator assembly require replacement. The dealer advised that the vehicle cannot be driven and is considered down. The vehicle/components are available for inspection upon request. My safety concern is that this is a brake-system malfunction serious enough that an authorized Toyota dealer has determined the vehicle cannot be driven. Toyota previously established Customer Support Program ZJB addressing internal malfunctions of the brake booster and brake booster pump assemblies in 2011–2015 Prius vehicles. Toyota’s documentation specifically identifies C1391 as a diagnostic code associated with this condition. My Prius has only approximately 102,000 miles, well below the program’s 150,000-mile limitation, but is outside its 10-year time limitation. The Toyota replacement part required to repair the brake system is now backordered with no known timeframe for availability. Because Toyota has advised the vehicle cannot be driven, it will remain out of service until the part becomes available. I am reporting this because a previously identified brake-system failure continues to occur after Toyota’s support period expires. I ask the federal safety agency to consider whether continued C1391 brake booster/accumulator failures in these Prius vehicles warrant further investigation or safety action.

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 Aug 3, 2026 · Brakes, Electrical · HI

I am submitting this complaint regarding a serious safety concern involving the brake actuator/booster assembly on my 2014 Toyota Prius. My vehicle has experienced failure of this critical braking component and has been unable to be properly repaired since November due to difficulty obtaining the correct replacement parts. This involves a major safety system required for proper braking operation. Brake actuator/booster assembly. Diagnostic codes: B1206, B2321, C1252, C1253 C1256. Toyota previously acknowledged brake actuator concerns through Customer Support Program ZJB. However, my vehicle is outside the program limits despite experiencing what appears to be the same type of failure reported by many other Prius owners. Since November, I have faced difficulty obtaining the correct parts, reports of nationwide backorders or limited availability, conflicting information regarding updated Toyota part numbers, and concerns about repair providers advertising new OEM parts that may actually be aftermarket or incorrect components. This creates a safety concern because owners experiencing brake failures may be unable to obtain timely repairs using verified, appropriate parts. Repair estimates have ranged from approximately $3,000 to over $4,000, including a Toyota dealership estimate of approximately $4,100. This creates a significant barrier to restoring a vehicle to safe operation, especially involving a component Toyota has previously addressed through a customer support program. I request that the federal safety agency review this complaint and similar reports to determine whether further investigation is warranted regarding Toyota Prius brake actuator failures, parts availability issues, and whether additional manufacturer action or support is needed. A vehicle’s braking system is a fundamental safety component. Owners should be able to obtain a safe and reliable repair without months of delay or uncertainty regarding replacement parts.

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 Jul 1, 2026 · Brakes · TX

I am filing a formal safety complaint regarding a catastrophic brake component failure on my 2013 Toyota Prius, occurring at less than 83,000 miles. The vehicle’s Brake Master Cylinder/Actuator Assembly has suffered an internal hydraulic pressure leak, causing the electric booster pump to run continuously to prevent a total loss of braking assist. This is a well-documented manufacturing defect that directly compromises passenger safety, drastically increases stopping distances, and threatens a complete loss of power assist while driving. Toyota explicitly acknowledged this inherent design flaw through its Customer Support Program (ZJB). However, they limited coverage to a strict 10-year expiration date from the first date of use. Because my vehicle has exceptionally low mileage and was driven gently, the component took longer to degrade, causing it to fail just outside Toyota's arbitrary time limit. Limiting safety coverage based on time rather than mileage penalizes owners of low-mileage vehicles for an engineered factory defect.

Filed Jun 23, 2026 · Brakes · CA

On June 20, 2026 while driving the Toyota Prius I experienced a sudden brake failure. Initially I thought I might have pressed the accelerator instead of the brake. But then pressing the brake I found the car did not stop and the ABS brake, brake lights, and other lights lit up on the dash board. The car had only 61,150 on the odometer. I called on Toyota for their warranty coverage but they declined saying that the vehicle is no longer covered. This brake failure should have been under Recall. AAA auto service has pulled C1391 vehicle code - requiring removing and replacing brake booster pump assembly with master cylinder, etc.

Filed May 7, 2026 · Brakes · KS

I own 2 2009 Toyota Prius. Both cars less than 175,000 miles and both have failed ABS modules. The ABS module in this vehicle is also the power brake booster. This failure can cause braking issues such as loss of braking or sudden brake application. Only known fix is replacement of the ABS brake module which requires the Toyota Techstream service computer.