Toyota Prius warning lights comes on

Filed Oct 19, 2026 · Brakes · CA

On XXX, at approximately 152,570 miles, the brake, ABS, and traction-control warning lights illuminated at the same time on my 2013 Toyota Prius. The brakes felt spongy, and I heard a recurring buzzing sound approximately every 3 seconds. Because of the change in brake-pedal feel and concerns about braking safety, I stopped using the vehicle. I reported the problem to Longo Toyota in [XXX], which directed me to Toyota customer support. The vehicle was subsequently diagnosed with trouble code C1391, “Internal Leak in Accumulator.” I contacted the dealership and Toyota customer support about Customer Support Program ZJB, which addressed code C1391 brake booster and brake booster pump failures. Toyota denied coverage because the failure occurred outside the program’s time and mileage limits. The symptoms began only 2,570 miles beyond the 150,000-mile limit. My primary concern is **safety**, not simply the expiration of coverage. The vehicle developed spongy brakes, multiple warning lights, and frequent buzzing. The diagnosis appears consistent with the type of brake-system failure Toyota previously addressed through ZJB. I request that the federal safety agency investigate whether this condition constitutes a safety defect affecting 2013 Toyota Prius vehicles and whether a recall or other corrective action is warranted, including for vehicles that develop the failure after the support program expires. I can provide the diagnostic report and available supporting records. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jun 25, 2026 · Brakes · CA

The vehicle experienced a failure in the braking system involving the brake booster/brake actuator assembly. The vehicle displayed diagnostic trouble code C1391, which is associated with a malfunction of the brake booster pump/accumulator system on this model. The failed component is available for inspection upon request. The failure created a safety concern because the braking system warning lights illuminated and the vehicle’s brake assist system may not function properly. A malfunction of the brake actuator/booster system could increase stopping distance, reduce braking performance, and create a potential risk of a crash, especially during emergency braking situations. The problem has been confirmed through diagnosis showing the C1391 trouble code. The issue has been identified as a brake system malfunction requiring repair of the brake booster/actuator assembly. The vehicle has been inspected/diagnosed by a service professional. The vehicle has not been inspected by police or insurance representatives. Toyota/dealer inspection information is available if requested. I contacted Toyota regarding the issue, but they declined assistance because the extended warranty coverage expired approximately 7 months prior to the failure. Before the failure, the vehicle operated normally. The first symptoms occurred when multiple warning lights appeared while driving, including the ABS warning light, brake warning light, parking brake warning light (even though the parking brake was not engaged), and the traction control/slippery road warning light. These warning lights appeared suddenly, indicating a problem with the braking system.

Filed Apr 21, 2026 · Brakes · AL

The brake cylinder assembly and the brake booster pump assembly failed while driving, which made braking very difficult, caused the regenerative braking to stop working, and caused multiple warning lights to come on. No warning lights, messages, or other symptoms were present prior to the sudden failure. This sudden failure could have easily resulted in a crash and/or death(s). I brought the vehicle to a Toyota dealership, and they confirmed the above issue and replaced the parts. I was told by the dealership, and also read online, that this is a known issue of Toyota for my vehicle and that Toyota extended a warranty years ago; however, the extended warranty is no longer valid for this known defect.

Filed Mar 4, 2026 · Brakes · CA

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.

Filed Feb 27, 2026 · Brakes · DC

While driving my 2013 Toyota Prius (110,691 miles), multiple warning lights suddenly illuminated on the dashboard, including the ABS, Brake, and Stability Control lights. I initially took the vehicle to an independent specialist (DC Line), but the mechanic there suggested I take it directly to Toyota because his staff recognized this as a known manufacturing defect that should be covered by the manufacturer. A Toyota dealership confirmed diagnostic code C1391, which indicates an internal high-pressure leak in the brake actuator and booster assembly. This is a critical safety defect that causes the brake pedal to become soft and unpredictable, significantly increasing stopping distances and disabling the ABS system. This poses a direct threat to my safety and others on the road. Toyota is fully aware of this defect through Customer Support Program ZJB, but they are refusing to cover the repair because of an arbitrary expiration date they set for 2023. I am currently 40,000 miles under the 150,000-mile limit Toyota established for this exact part failure, yet they are using the 2023 calendar date to deny coverage. Furthermore, I was never properly informed of this defect. Toyota claims they sent a single notification card in 2018, which I never received. I am now being forced to pay $3,000 out of pocket for a manufacturing flaw that even independent mechanics recognize as Toyota’s responsibility. It is unacceptable that a manufacturer can avoid responsibility for a dangerous braking failure by relying on a single postcard and an arbitrary 2023 deadline on a vehicle well under the mileage limit. This should be a mandatory safety recall, as the safety of a vehicle's braking system should not depend on a postcard or a calendar date.

Filed Feb 14, 2026 · Brakes · MD

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.

Filed Jan 25, 2026 · Brakes · MO

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

Filed Jan 5, 2026 · Electrical, Lights · CA

My Prius suddenly malfunctions and goes berserk randomly. No other way to describe it. I've taken it into the dealer twice, and I'm not confident I'm driving a safe car. I've not done anything to the car and it has not been in an accident. It's unclear why it does it. When it has an episode it is not safe to drive, won't turn on and won't turn off. The alarm goes crazy. Nothing works, all the dash lights turn on. I have videos. This has happened about five times and I've been called back from the dealer to pick it up. I"m not confident it is safe to drive, and I don't think Toyota is taking my concerns seriously. The vehicle has about 7400 miles and is otherwise pristine. All service is up to date. It is a lease.

Filed Dec 25, 2025 · Brakes, Electrical · NY

While driving, the vehicle experienced a sudden brake system malfunction without prior warning or gradual degradation. The vehicle was being operated under normal driving, road, and weather conditions. No recent brake service, repairs, or aftermarket modifications had been performed prior to the failure. Multiple warning lights illuminated on the dashboard, including the ABS warning light, brake warning light, and traction control warning light. Shortly after the warning lights appeared, the vehicle began emitting continuous warning beeps. Audible buzzing or pumping noises were also present from the brake system during the malfunction. During this event, brake performance was reduced and braking felt inconsistent. The brake pedal became hard at times and spongy at other times, requiring increased effort to slow the vehicle and resulting in unpredictable braking response. This created a safety concern while the vehicle was in motion. The driver was forced to alter driving behavior and exercise extreme caution due to reduced braking confidence and unpredictable pedal feel. The malfunction has occurred intermittently during normal driving. The condition temporarily resolves on its own and later reoccurs without corrective action. The suspected failed component is the brake actuator / ABS actuator assembly. A diagnostic scan retrieved fault codes C1252 (Brake Booster Pump Motor ON Time Abnormally Long), C1253 (Pump Motor Relay Malfunction), and C1256 (Accumulator Low Pressure), which are consistent with brake actuator malfunction. The failure occurred at approximately 154,000 miles. This vehicle model and generation have a documented history of premature brake actuator failures with similar safety-related symptoms reported by other owners. The condition places the driver and others at risk due to unpredictable braking behavior, reduced braking effectiveness, and repeated warning alarms while driving. Warning lamps and audible alerts continue intermittently.

Filed Dec 9, 2025 · Brakes · CA

The Master Cylinder started failing while I was driving the car, the car only has 138k miles, the dashboard lit up like a Christmas tree, all the warning lights were on, and when I went to step on the brake, I had to push it all the way to the floor for any braking to happen. I remember being scared for my life because I had almost no brakes which I could've got into a serious accident or been killed had it failed completely. I took the car to the dealer and they diagnosed it with code C139: Abnormal Leak at Accumulator Assembly, and recommended a new Brake Booster with Master Cylinder Assembly and Brake Booster Pump Assembly with Bracket. The car by age was not in Toyota's extended warranty on the parts but mileage-wise it still is, so I was footed with a $4-5k bill to replace both parts.