2012 TOYOTA PRIUS Complaints

The brake booster and brake booster pump assembly (also referred to as the Accumulater or Accentuater) have failed in my vehicle the same as Toyota's known defect that was mentioned in their Customer Support Program 20TE07 (part numbers can be found within the filing of their CSP 20TE07). I am reporting that this issue appears to have affected more than their initial estimate of ~118,960 states impacted vehicles.l because Toyota is declaring my vehicle is outside of their CSP 20TE07 although their defect endangers my safety (and the safety of others) and attempts to put their defective vehicle brake parts as my financial burden. This issue should have been/should be a larger recall. Thank you.

2012 Prius with 174,344 miles in great condition, with regularly scheduled oil changes. ABS/Break Actuator failure on freeway with no warning other than a beep a few seconds before the breaks disappeared completely. Break pads changed 4 months ago and new wheels installed as well. This is a known problem with Toyota under the TSB002419 where Break booster actuator was put on a customer service program to be fixed by the dealerships, but has since expired since 2022. The cars are still known to have their breaks go out due to this malfunction but it is now not covered by Toyota and cost $4K-$5K to fix which is more than the market value of the car today. This needs to be fixed and regulated.

Odometer Fraud. The contact purchased a 2012 Toyota Prius. The contact stated that while attempting to register the vehicle, it was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. At the time of purchase, the vehicle mileage was 187,000, and at the time of registration, it was discovered that the mileage was 227,000.

The contact owns a 2012 Toyota Prius C. The contact stated that while driving 20 MPH, the message "Check Hybrid Status - Stop vehicle in Safe Place Immediately" was displayed. There were several warning lights illuminated. The vehicle was towed to the local dealer, where it was diagnosed with an internal power module transmitter and MG control computer inside the inverter assembly failures. The vehicle was not repaired. The contact called an independent mechanic, and DTC: P0A94 (DC/DC converter or inverter performance problem invertor assembly) was associated with the failure. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 98,015.

The contact owns a 2012 Toyota Prius. The contact stated while driving at an undisclosed speed, several unknown warning lights illuminated, with an abnormal sound coming from the vehicle. The vehicle was taken to the dealer where it was diagnosed with brake booster failure. The contact was informed that the brake booster pump needed to be replaced. The vehicle was not repaired. The contact stated that the failure was a known failure with the vehicle. The manufacturer was made aware of the failure. The contact was informed that an undisclosed Extended Warranty Program had expired. In addition, the contact was informed that the repair was not covered. The failure mileage was approximately 175,000.

My Brake Booster/Actuator failed on me while on the freeway with out any warnings. It made it really hard to stop the car. I didn't find out what it was untill I took it into a repair shop and they told me it was the Brake Booster/Actuator.

The vehicle is experiencing a suspected brake actuator / brake booster failure. Multiple warning lights appeared simultaneously, including ABS, Brake, Traction Control, and Master Warning lights. The vehicle produces a frequent buzzing noise from the brake system, especially at low speeds or when stopped. The noise occurs repeatedly when pressing the brake pedal, indicating the system is struggling to maintain hydraulic pressure. This condition raises serious safety concerns because it may reduce braking performance and increase stopping distance. Brake system failures present a significant risk to vehicle occupants and others on the road. After researching the issue, I learned this appears to be a common failure in Toyota Prius vehicles of similar model years, and Toyota previously issued extended warranty coverage for the brake booster/actuator assemblies. However, many vehicles now exceed the coverage limits despite the safety nature of the defect. I am submitting this complaint because a failing brake system is a critical safety hazard, and this issue appears widespread.

Vehicle check engine code C1391 (Antilock Brake System - abnormal leak in accumulator) came up on 2/5/2026. Recommended repair is to replace the Brake Booster Pump and Assembly, Brake Booster - over $1000 in parts alone. This WAS covered by an Extended Warranty by Toyota (10 years / 150K miles). I only have 120K miles at this time but am past the 10 year mark. However, it seems that this part will fail in every Prius given time and encourage NHTSA to monitor these failures and hold Toyota accountable to address post the 10 year / 150K mile mark.

The contact owns a 2012 Toyota Prius V. The contact stated that while driving at an undisclosed speed, the brake master cylinder was constantly cycling. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic to be diagnosed or repaired. Most recently, while the vehicle was turned off, the brake master cylinder was cycling. The contact stated that while the keys were in his hands and standing several feet away from the vehicle, the brakes started cycling. The manufacturer was notified of the failure but offered no assistance. The approximate failure mileage was 140,000.

Vehicle: 2012 Toyota Prius Mileage: Approximately 217,000 miles While driving normally in traffic, the vehicle experienced a sudden and unexpected brake system failure. Multiple warning lights illuminated simultaneously, including the red BRAKE warning light, ABS warning light, traction control light, and warning symbol (!). Shortly after, the vehicle began emitting an audible warning/beeping, and there was a sudden loss of power brake assist. The brake pedal behavior changed abruptly: the pedal became very soft initially, then became suddenly hard halfway through travel, This failure occurred while approaching another vehicle in traffic, and I narrowly avoided rear-ending the vehicle in front of me. The unexpected loss of brake assist created an immediate and dangerous situation, as the vehicle did not decelerate as expected when the brake pedal was applied. Due to the seriousness of the brake failure and safety risk, the vehicle was removed from service and towed. This incident represents a critical safety defect, as sudden loss of braking assist while driving poses a significant risk to vehicle occupants and other road users. I am reporting this incident to document the hazard and request investigation into the reliability and safety of the brake system design. I am requesting you to please issue a recall and reimburse me , as these parts are very expensive , it affected my financial situation, Thanks