2011 Toyota Prius: multiple warning lights

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a known issue of Toyota for my vehicle and that Toyota extended a warranty years ago; however, the extended warranty is no longer valid for this known defect.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 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.

Filed May 10, 2025 · Brakes · TX

My ability to break unexpectedly stopped working while I was on the highway during morning, rush-hour. I was going 55 mph on the highway at the time and luckily, I was on an uphill incline when they went out, thus allowing me to be able to ‘naturally’ slow down. But had I not been on an incline at that time of the brakes faulting, I would have 100% caused a wreck because I could not break at all. My emergency breaks weren’t even working, which is confusing because I thought that was the whole point of the emergency break, was for if your regular brakes become faulty… But NONE of my brakes worked. Which has created a new fear I didn’t know could happen while driving… Also, all the lights that have to do with the breaking system were on (ABS, Traction control, BREAK lights). And a consistent building up hissing noise under the hood.

Filed Sep 8, 2024 · Brakes · IL

Symptoms: The vehicle exhibits a constant and repetitive noise when the brake pedal is pressed. Additionally, multiple warning lights are illuminated on the dashboard, including the red brake light, yellow ABS light, yellow traction control light, and tire pressure light. Suspected Cause: The issue appears to be related to the brake actuator or accumulator. This may be associated with Diagnostic Trouble Code (DTC) C1391, indicating an abnormal leak in the accumulator. This problem causes the brake booster pump to run continuously to maintain pressure, leading to the warning lights and noise. Safety Concerns: The malfunctioning brake system components could compromise the vehicle's braking performance and overall safety. Purchase Details: The vehicle was purchased recently from a dealership, and the issue was not present at the time of purchase.

Filed May 15, 2024 · Brakes, Electrical · 147,000 miles · AL

The contact owns a 2011 Toyota Prius. The contact stated that upon starting the vehicle, there was an abnormal beeping sound heard. The contact stated that several warning lights were illuminated. While reversing in the driveway, the brake pedal was depressed to the floorboard before the vehicle stopped. The contact's husband an independent mechanic informed her that the brake actuator needed to be replaced. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was approximately 147,000.

Filed Mar 14, 2024 · Brakes, Electrical · 204,000 miles · OH

The contact owns a 2011 Toyota Prius. The contact stated that the battery was drained frequently upon starting the vehicle. There was no warning light illuminated. The contact also stated that while driving at various speeds, the brake pedal was firm while depressing, with several warning lights including the ABS warning light illuminated. The vehicle was taken to a dealer and based from the noise coming from the vehicle; the mechanic determined that the brake booster and brake booster assembly were defective. The manufacturer was notified of the issue. The vehicle was not repaired. The failure mileage was approximately 204,000.

Filed Jun 7, 2023 · Brakes · 159,000 miles · NY

The contact owns a 2011 Toyota Prius. The contact stated while driving 50 MPH, the check engine, service brakes, ABS, and the traction control system warning lights were illuminated. The contact parked the vehicle on the side of the road for approximately 3 minutes before continuing to drive to her residence. The contact stated on March 17, 2023, while her husband was approaching a traffic light, the brake pedal was depressed but failed to stop the vehicle properly. The contact stated that several warning lights were illuminated. The driver stated that the vehicle cruised to a stop independently. The driver decided to drive at a slow speed to the residence. The contact took the vehicle to the local dealer, where it was diagnosed and determined that the brake master cylinder, the brake pump assembly, and the brake booster needed to be replaced. The vehicle was repaired. The manufacturer had been informed of the failure. The failure mileage was approximately 159,000.

Filed Apr 29, 2023 · Brakes · 133,000 miles · OK

Brake actuator failed while driving down the road on Friday, 04/14/2023. The car became hard to slow down/brake. Brake light, traction control light, ABS warning lamp came on, and tire pressure lamp came on. Next day lights went out. Then again all lights as above came on while driving down the highway. That was Wednesday 04/18/2033. Took to Toyota dealership who confirmed brake actuator had failed. Car has 133,000 miles on it. Prius was in the repair shop at Norton Toyota of Tulsa, OK, from Thursday 04/27/2023 until Saturday 04/29/2023.

Filed Dec 13, 2022 · Brakes, Electrical · NJ

I have reported this once and numerous times to Toyota. I even paid to "fix" the problem. My daughter was driving and all the dashboard lights came on and the brakes do not work. It's doing it again after they supposedly "fixed" it. My family is at risk! If anything happens, I will seek legal action. I can't believe a company as big as Toyota wont take responsibility. And that a recall wont be done. I've seen numerous people report the same issue. PLEASE do something.

Filed Jul 27, 2022 · Brakes · NY

While driving at roughly 58mph, while going around a turn: multiple dashboard lights came on, Tire pressure, traction control, emergency brake, one other. My brakes became less responsive (roughly half braking strength). This is consistent with the pseudo recall offered by Toyota covering my vehicle for a limited time, for which no notice was given and no warnings were sent.this issue has caused over five dozen crashes and during the duration of the recall, vehicles were not eligible until the braking system had failed. There were no signs of the faulty part until after the extended warranty period had expired, but the issue is the warrantied part, and the failure is consistent with the failure caused by the manufacturing defect responsible for the extended warranty effective in 2017

Filed Feb 5, 2022 · Brakes, Electrical · NJ

My daughter was driving the vehicle on highway and all dashboard lights came on. Abs brake and traction. The brakes would not work. She had to decelerate and pull off and turn car off. Terrifying. Got it checked at Toyota. Told them about that and how car lunges forward when brakes hit on a bump or pothole. We had to pay 2500 to replace brake booster which had an “internal error”. Got car back and all lights came back on. I’m literally terrified to drive my car because of what may happen. Toyota refuses to recall and fix whatever this issue is.

Filed Mar 6, 2020 · Brakes, Fuel system · 101,000 miles · GA

Tl* the contact owns a 2011 toyota prius. The contact stated that while driving at an undisclosed speed, several warning lights displayed on the instrument panel. The contact stated that the brake pedal was depressed and went to the floorboard which extended the braking distance. The vehicle was included in the federal safety agency campaign number: 18v684000 (hybrid propulsion system). The vehicle was taken to marietta toyota located at (750 cobb pkwy s, marietta, ga 30060 (470) 938-8430). The dealer declined to offer the repair because the vehicle had a salvage title. The manufacturer was contacted and offered a software update of the hybrid system but declined to offer any additional repairs. The failure mileage was 101,000.