2014 Toyota Prius

On April 5, 2026, while driving downhill around a corner in my 2014 Toyota Prius, the brake booster and brake booster pump assembly failed without any prior warning. When I pressed the brake pedal the car did not slow down and instead appeared to accelerate due to a complete loss of braking assist. I was unable to stop the vehicle normally and had to rely on gravity and coasting to slow down, creating a serious risk of collision. There were no warning signs prior to the failure. Immediately after the incident, three warning lights illuminated on the dashboard: the BRAKE light, the ABS light, and the VSC (vehicle stability control) light, which have remained on since. The vehicle was taken to DARCARS Toyota Baltimore, 6007 Eastern Ave, Baltimore, MD 21224, where the failure was confirmed on April 15, 2026. Technician Victor Lawson diagnosed diagnostic trouble code C1391, which is the exact qualifying code listed under Toyota's Customer Support Program ZJB for brake booster and brake booster pump assembly failure (RO# XXX). The vehicle remains at the dealership and is available for inspection. Toyota corporate was contacted and opened case number XXX but declined to cover the repair despite this being a documented issue that Toyota has publicly acknowledged. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving, three warning lights suddenly appeared on the dashboard . Abs warning, traction light, and break warning light At the same time, the brake pedal became very hard to press, and the vehicle did not slow down as expected. This caused a significant increase in stopping distance, and I nearly rear-ended the vehicle in front of me. The issue appears to involve the braking system and created an immediate safety risk. No prior warning signs were noticed before this incident. The vehicle has not yet been inspected but is available for inspection upon request.

Subject: Brake Booster/Pump Assembly Failure – Toyota Program ZJB / 23TE07 Description of Incident: I am reporting a failure of the brake booster and pump assembly on my 3rd Generation Prius (82,000 miles). While the vehicle is 11.3 years old, it is well under the 150,000-mile threshold of Toyota’s Customer Support Program ZJB. The brake pump began cycling every 13 seconds, indicating an internal pressure leak in the accumulator. This is a documented precursor to a total loss of power-assist braking. Despite the clear mechanical failure, no warning lamps or Diagnostic Trouble Codes (DTCs) were triggered, creating a safety hazard where the system could fail without prior electronic notification. Repair and Cost Details: Because the vehicle was 1.3 years past the arbitrary 10-year "Secondary Coverage" window, I was forced to pay $3,461.18 out-of-pocket for a known manufacturing defect. I would like to highlight a discrepancy in labor billing: while Toyota’s own technical bulletins (ZJB/23TE07) state the repair should take approximately 5.3 hours, the dealership charged 8.9 hours of labor for the same procedure. Safety Concern: By limiting coverage to 10 years, Toyota has left many low-mileage owners with a critical safety defect that degrades over time regardless of mileage. I request that the NHTSA transition this from a "Customer Support Program" to a formal Safety Recall to ensure all affected vehicles are repaired and owners are reimbursed, regardless of the vehicle's age.

the cylinder head gasket blew because of the poor design of the intake manifold and the EGR system. There are updated parts to fix this issue, but there was no recall. This poor design led to the vehicle having "the Death Knock." It started doing this knock on my trip driving my daughter to college. The engine could have seized in traffic on the way to [XXX] from [XXX] . No warning lights came on telling me there was an issue. The vehicle is being taken apart now to see if my connecting rods were bent from the coolant entering the combustion chamber. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2014 Toyota Prius. The contact stated that while driving at an undisclosed speed, the vehicle failed to slow down as intended with the brake pedal depressed. The ABS warning light was occasionally illuminated. The vehicle was pulled over to the shoulder of the roadway and restarted. The vehicle was taken to a local independent mechanic, where it was diagnosed, and determined that the brake master cylinder, brake booster, and brake lines needed to be replaced. The local dealer was contacted; however, the vehicle was not diagnosed or repaired. Upon further investigation, the contact related the failure to an undisclosed recall; however, the VIN was not included in the recall. The manufacturer was notified of the failure. The contact was referred to the NHTSA Hotline for assistance. The failure mileage was approximately 152,000.

Vehicle: 2014 Toyota Prius v Hybrid Mileage: 79,000 miles The vehicle experienced sudden failure of the brake booster / brake accumulator system. Multiple warning lights appeared including ABS, traction control, and the red brake warning light. Diagnostic code C1391 was retrieved. The brake pedal became soft/spongy and the electric brake pump began cycling frequently. Braking performance felt reduced and inconsistent, creating a potential safety risk. This vehicle has very low mileage (79,000 miles) and has been well maintained. The failure appears to be related to a known defect in the Prius braking system. Toyota previously issued Customer Support Program 20TE07 addressing brake booster and pump failures on 2012–2014 Prius v vehicles. Despite this known issue, the repair is not being covered and the cost quoted is several thousand dollars. A failure of the brake booster/accumulator system significantly affects braking performance and should not occur at this mileage. This appears to be a widespread issue affecting Prius vehicles and represents a potential safety defect involving the braking system.

Head gasket failure. No check, engine, light or warning. My car was very well maintained regularly. After research, I found this to be a very common problem. Yes it is available for inspection. Upon request. The problem was confirmed by chemical test, ignition vapors going into engine coolant. Other symptoms were misfiring on cylinder two and cylinder four. Severe engine knocking.

The brake booster/accumulator failed on my vehicle. This part was a common failure during the 2010-2015 production run so much so that Toyota extended coverage to replace. Mine failed recently beyond the warranty extension of 10 years/150k miles. My vehicle has only 108k miles and is 15 months beyond warranty. Toyota Corporate will not replace this vital part, despite the fact it was a defective design. I can’t drive it any longer since I don’t have the $4000 to make repair. Toyota Corporate has shown little concern despite this critical safety defect.