2011 Toyota Prius: sudden loss of power

Filed Sep 14, 2026 · Brakes · VA · crash

I am filing this complaint to report an active, severe safety defect involving a sudden, un-warned loss of power braking assist due to a failing factory brake actuator/booster pump assembly. My vehicle is exhibiting the exact internal hydraulic seal failure, pressure drop, and audible hissing/sipping sound outlined in Toyota's prior technical service bulletins. Because the onboard ECU computer only triggers warning lights once a complete, catastrophic failure threshold is met, the system is currently masking the defect from the dashboard. However, the physical hardware is actively failing, requiring the high-pressure pump to run constantly to maintain braking pressure. This component failure dramatically increases stopping distances and presents an immediate, unreasonable risk of a crash. Toyota previously acknowledged this widespread manufacturing defect via Customer Support Program ZJB (20TA02). However, because Toyota chose to manage this critical safety hazard through a time-limited warranty extension rather than a mandatory safety recall, hundreds of thousands of vehicles are now left with a catastrophic braking hazard because the consumer coverage expired in 2022. I urge the federal safety agency to open a formal defect petition review to investigate these post-warranty failures and mandate a retroactive safety recall to protect the public.

Filed Aug 18, 2022 · Brakes · CA

This issue started happening intermittently beginning in April 2022. The ABS/Traction Control/Emergency brake lights came on all at once and the car lost power braking ability. The car would stop, but it required much more force on the pedal and an increase braking distance. Folsom Lake Toyota Service said that there wasn't anything they could do if the warning lights had turned off and to try to recreate the issue. It happened again in May 2022 while my daughter was driving the car back from Tahoe. She was not hurt, she avoided an accident. The car returned to normal operation after it was parked for one day. It happened again in July of 2022. This time the brakes hissed when applied. Called Folsom Lake Toyota to have it looked at. They diagnosed it as error code C1391 and the master cylinder (acctuator) and brake booster needed to be replaced. The repair was $3200, so we took the car to Roseville Toyota for a second opinion. Roseville Toyota was able to recreate the issue and the brakes completely failed at their service center. Their estimate was for the same $3200 repair. We called Toyota Corporate and they responded that there was a Toyota Customer Support Bulletin ZJB sent out for this issue. The bulletin extended the factory warranty on the parts for 10 years or 150,000 miles. The bulletin describes the exact code and symptoms our car experienced. Our car is 11.5 years old and 113,000 miles. In speaking with Toyota Corporate, their position is that they already extended the factory warranty once and since that our car is past the 10 years, they refuse to consider my complaint or provide any "goodwill" assistance with the repairs. Toyota knows there is an issue with their master cylinder and brake booster parts. They set an arbitrary warranty extension date rather than recalling the cars. Toyota is waiting for the brakes to fail BEFORE they fix the problems. My daughter could have been seriously injured or killed, or she could have killed someone else.

Filed Sep 26, 2021 · Brakes, Electrical · CA

one year after bought, was losing power, replacing a lot of batteries, headlights and lamps then car would lose power while driving, not start continually everyday for each day after and even started on its own. i took in a lot and they put my vin to the wrong person..someone rainsford so my service recs were not recorded. said no battery code, didnt check altenator, and even tho serv advisor said the break was squishy to him and he heard the loud buzz noise when pushing, it was not replaced. they tried to blame it on keys being in car which is how it starts and runs! not parked on hill or in bad temps and driven long trips, none of which SHOULD BE REQIRED to start a car to get to dying patients on time. we bought charger and use on both priuses daily. lost power while driving, got hurt, and josh's pt. died. nothing but headache nightmares. have long written records where submitted all and they just like to deny things or try to find a way to blame on consumer. my only fault was buying an undisclosed deathtrap. they need to refund us both cars and damages and expenses and our time and missed work. the shuttle was a joke. i have my own top notch code reader and it said battery was fine. it was new, yet they wanted to sell me one so they said it coded but refused to show me. they are just trying to make money and really hurting people. sending my title and all my personal info to a stranger and me catching after 7 years broght on an ID theft im still fighting. very rude front staff and drivers..sheldon.

Filed May 12, 2020 · Fuel system · 115,000 miles · WA

While driving down city street at approx. 25 MPH, the vehicle suddenly lost all power and had to be emergency steered without power steering to the side of the road, narrowly avoiding a crash. The dashboard showed "check hybrid system"; vehicle was inoperable and had to be towed.

Filed Dec 24, 2019 · Brakes · 118,000 miles · AZ

The brake system appears to break down; ABS module and brake booster lose power. This causes braking to be harder and potential safety for the vehicle to lose all braking capability. This issue occurs when braking. There appears to be less air pressure in assist in the braking. Reading online this is a very common issue for the 2011 vehicle! The 2010 model had a recall due to manufacture defect. Https://www.carcomplaints.com/toyota/prius/2011/brakes/service_brakes.shtml please address soon because this is a major safety issue!

Filed Oct 18, 2019 · Engine, Fuel system · 158,000 miles · CA

I was making a left turn at a very busy los angeles intersection and during needed acceleration to turn, the prius lost power for a full second and then power came back slowly and I barely made it through the intersection, a t bone collision was imminent, and I missed getting hit by inches. All the warning lights on the dash illuminated and I was frazzled. The hybrid battery was 2/3 rds full at the time. There have been other instances where the car lost power for brief moments when the hybrid battery was low and didnt think anything of it at the time. The mpg has remained below 40 and after hybrid failure, around 26. Also, I had a gen 2 prius and the catalytic converter went bad around 150,000. California punishes consumers by not allowing after market cats and forces them to buy oem at an extreme mark up. Without a proper cat, you cant have cal smog approval, no approval, no registration. Total waste of resource when the actual cost of replacement of the cat is around $2k at the dealer. If I lived in az, after market is $475. At that point a car of that age and milage is worth around $2-3k. Battery and cat replacement costs should not eclipse the value of the car. Still doesn't mention the rest of the mechanical and saftey apparatus . If an engine works half time on a hybrid, why does the cat burn out so soooon? The scam is baked into the vehicle and our govt supports it. Fix carb!

Filed Aug 23, 2019 · Engine, Transmission · 57,000 miles · VA

Car stalled pulling into traffic. Took about 15 sec to restart. No diagnostic lights lit up on dash. Car lost power last month and engine light went on and engine could not be restarted.had to be towed to dealership. It replaced valve assembly for vacuum and reprogrammed PCM. However, that issue was preceded by a creep of diagnostic lights (course of 1 hour), from check oil to check engine, and then it completely shut down.

Filed Oct 24, 2018 · Airbags, Electrical · 72,000 miles · CA · crash · 1 injury

Tl* the contact owned a 2011 toyota prius. While driving 40 MPH, the vehicle lost power without warning. As a result, the contact crashed into a tree and a cement barrier. The air bag failed to deploy. The vehicle was restarted and was able to be driven to the contact's residence. The contact sustained back, neck, and chest injuries that did not require medical attention. A police report was not filed. The vehicle was not taken to a dealer or independent mechanic for diagnostic testing. The vehicle was later deemed destroyed. The contact stated that the VIN was included in the federal safety agency campaign number: 18v684000 (hybrid propulsion system). The manufacturer was notified of the failure and provided a case number. The approximate failure mileage was 72,000.

Filed Oct 22, 2018 · Acceleration, Engine · 113,000 miles · FL

In motion while accelerating past a slower car. Heard and felt a pronounced thump and lost engine power on busy local thoroughfare. Moved to a turn lane and stopped. Multiple dashboard lights and "check hybrid system" on LED display. Power off car, and back on twice and got the same error on display. Found that car could move on EV power and I got it into a safer location at an adjacent parking lot. Had vehicle towed to repair facility. As a driver this was disconcerting as I could not clearly determine if the car was at all driveable. If a driver were to stop immediately in the same situation they would be on the roadway. If I had not pressed on the accelerator pedal after powering on the car again I would not have known I could move the car to a safer location. Display should read "hybrid system failure" then "limited EV power available" then "move to safe area if necessary" cause: hybrid inverter failure. Repaired by toyota under 2014 eoe and new 10/2018 recall j0a

Filed Aug 23, 2018 · Brakes · 111,090 miles · SC

While driving on the highway, without warning, I lost power assisted breaking ability - accompanied by a number of dashboard warning lights. I was able to safely stop the vehicle using manual breaking. I had the code checked and have learned that the (code 1391) brake accumulator failure is a common issue in the prius and has been subject to a recall/replacement for the years prior to my make (I believe 2008-2010). Clearly this is still an issue and the sudden/no-warning failure of the system causes an alarming and potentially dangerous loss of breaking control during high speed driving. Luckily, I was not using the breaks at the time of the failure and was able to determine that the manual break pads were serviceable but I needed to rapidly increase the pressure on my breaks to slow down sufficiently to avoid an accident.

Filed Jul 18, 2018 · Electrical · 100,000 miles · CA

I was driving along on the freeway trying to get home and suddenly my prius lost power. I was panicking, good thing I had my brothers with me or else I would have lost it. We didn't know what was going on! We managed to get off the freeway safely, but we were distressed.

Filed Apr 13, 2018 · Brakes, Electrical · 165,000 miles · SD

I was getting on the interstate and all of a sudden I lost power and my dash lite up check hybrid system /ABS/ breaks. I can not drive my car because it has no power please help thank you