2012 Toyota Prius: ABS light or ABS activating

Filed Nov 1, 2026 · Brakes · NV

I own a 2012 Toyota Prius with approximately 132,000 miles. I first experienced problems with the braking system approximately one year ago, in 2025. The ABS, brake, and other warning lights began illuminating intermittently, and I experienced occasional hesitation in braking response. I was concerned enough about the vehicle's safety that I stopped driving it for an extended period. After recently returning the vehicle to service, the warning lights continued to appear intermittently, even when the brakes seemed to function normally. An independent mechanic inspected the vehicle but could not retrieve a diagnostic code at that time. On November 1, 2026, an ABS diagnostic scan at O'Reilly Auto Parts confirmed trouble code C1391, "Abnormal Leak of Accumulator Pressure." The diagnostic report recommended replacement of the brake booster and master cylinder. Toyota previously acknowledged this brake booster problem through Customer Support Program ZJB, which covered certain 2010–2015 Prius vehicles with this defect. Despite my vehicle having fewer than 150,000 miles, Toyota informed me that the coverage period had expired and that no exceptions would be granted. I am concerned that this known braking system defect can develop in vehicles that remain in service after Toyota's limited coverage expires. The intermittent nature of the malfunction makes it particularly concerning because the brakes may appear normal even when an underlying hydraulic pressure problem exists. I request that the federal safety agency investigate whether this defect warrants a safety recall rather than a time-limited customer support program. My diagnostic report is available, and the vehicle can be made available for inspection upon request.

Filed Oct 1, 2026 · Brakes · FL

When I started my car this morning, the red BRAKE light, ABS warning light and anti-slip light were all illuminated. The car does still stop but the brakes are very spongy and there's a clicking noise under the hood. I only moved the car out of the driveway to allow other cars to leave. The brake fluid is not low. This is the problem listed under Toyota's Customer Support Program Notice ZJB but it is past the coverage expiration date. There should not be an expiration date on a known manufacturer issue. If this had happened while I was on the highway driving to work, I could have had a serious accident.

Filed Jul 2, 2026 · Brakes · HI

My 2012 Toyota Prius is experiencing brake actuator pump failure, presenting diagnostic trouble codes C1253 (brake actuator pump motor stuck/locked) and C1256 (brake actuator pump motor overcurrent). These codes trigger ABS, brake, and VSC warning lights and disable ABS and stability control. Toyota previously acknowledged this exact defect under Customer Support Program ZJB, which covered 2010-2015 Prius vehicles for brake booster and brake booster pump assembly failures triggered by these specific codes. I am the original owner of this vehicle, purchased new in 2012. I never received notification of CSP ZJB despite being the registered owner at the time notifications were distributed in 2019-2021. My current mileage is under 150,000 miles, within the secondary coverage mileage limit established by the program. Toyota has declined to provide goodwill coverage citing program expiration. This is a known safety defect that reduces braking effectiveness and disables ABS — it should have been addressed through a mandatory recall rather than a voluntary program with an expiration date that left original owners without recourse due to failed notification.

Filed Apr 27, 2026 · Brakes · CA

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.

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 Dec 26, 2025 · Brakes · NC

My 2012 Toyota Prius plug in hybrid had just passed state inspections and was even looked at by a dealership a year ago with no reported issues. I brought up a whirring issue at the dealership when breaking but the dealership said that’s normal for a hybrid. In a matter of minutes while driving, the traction light, brake light, and ABS light came on as well as a groaning, whirring sound when breaking. Over time, the breaks failed and I could not stop the car, almost causing a wreck because I could not stop without putting all my body weight on the break pedal. When taking it to the Toyota dealership for a whole diagnostic, they said it was a break actuator and break booster failure that is known to happen with Prius’s. They quoted me $3000 for a repair and then marked my breaks as yellow not red on their sheet implying I could still drive it despite the dangerous situation of driving without functioning breaks. When looking into it, this seems to be a known and common problem with Prius’s due to a faulty manufactured part. Codes were c1391, wc1256, and c1252. I believe this part should be recalled and Toyota should fix these faulty parts, especially considering they inspected my car and did not mention it as an issue despite it being a known issue. I got a second opinion from Mavis Tires and they concurred with the diagnosis but could not fix it.

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 Nov 28, 2025 · Brakes · CA

While driving on a city road below the speed limit, braking was compromised leading to loss of traction and failure of the ABS system. During the incident, the brake, ABS, and engine warning lights all turned on and a collision was only avoided due to pumping of the brakes. Further investigation by a mechanic revealed a failure of the brake actuator system. Failure of this system has increased the stopping distance of the vehicle considerably and makes braking unreliable and unpredictable.

Filed Nov 6, 2025 · Electrical · NC

The hybrid system fails to enter “Ready” mode with no SMR engagement audible from the junction box. Dashboard displays ABS, brake, engine, and master warning lights. OBD codes include U0142, U0155, and previously U0073 . Rear brake lights function normally when pedal is pressed. Dealer said to pay 250$ for diagnostic and diagnosed incorrect voltage from brake light switch and quoted $348.94 to replace, but refused to proceed with open safety recall J0V / 18V684 (the federal safety agency 18V684000) citing inability to achieve “Ready” mode. Recall covers inverter failure leading to loss of motive power. Dealer declined to jump 12V battery or use external power to perform required software update and inverter inspection. Vehicle remains inoperable and poses safety risk due to sudden power loss potential. Component (inverter G9200-47141) available for inspection. Problem confirmed by dealer diagnostics. No police or insurance inspection. Warning lamps appeared after 12V battery replacement three months ago.

Filed Oct 31, 2025 · Brakes · MD

While driving 60 mph in highway, ABS, traction control and brake lights lit up and vehicle lost its effective braking power. There were no prior warnings prior to this failure. It was a sudden incident. Since it wasn't rush hour, I could safely reduce speed and bring the car to stop. Situation could have been much different if it was normal hours. After taking the car to dealership, it indicated DTC code 1391, Brake Assembly Failure. The car was fixed at dealership at cost of $3,000. When researched further, it appeared that there is broader pattern of failures. Numerous reports have been made by owners of 2010–2015 Toyota Prius, Prius PHV, 2012–2015 Prius V, 2012–2014 Camry Hybrid, and 2013–2015 Avalon Hybrid vehicles, all of which share the same brake booster pump assembly design manufactured by Advics Co., Ltd. Dealerships, including Capistrano Toyota and Claremont Toyota in California, have previously petitioned the federal safety agency regarding this very defect. Their 2019 letter to the agency documented that Toyota: * Knowingly excluded hundreds of thousands of hybrids from prior safety recalls (DOH 13V‑235 and KOL 19V‑544) despite identical failures. *Issued “post-failure” repair programs (Warranty Enhancements ZJB, ZKK, ZKC, ZLM, 20LE03, 23TE06 and 23TE07) only after owners experienced brake failure. * Identified the same DTC codes (C1252, C1253, C1256, C1391, U0293) in both recalled and unrecalled vehicles—codes that correspond to accumulator leaks, loss of brake pressure, and failure of brake assist and stability control systems. * Admitted through Technical Service Bulletin TSB-0130-19 that these defects caused loss of hydraulic pressure, increased stopping distance, and total loss of brake assist in affected hybrids. In short, the defect pattern across multiple hybrid models is identical to those already recognized by Toyota and the federal safety agency under prior recall campaigns, but for reasons unexplained, Toyota limited the recall population and left many consumers unprotected

Filed Oct 30, 2025 · Brakes · AZ

Traction control.Abs and brake warning lights all came on.