When I pressed the brakes while approaching a stop I hit a bump in the road (large pot hole). The pressure on the brake released for approximately 1 second before the pressure on the brake pad re-engaged. This same scenario can happen any where from 0 to 2 times per week. In the winter when the road surface is not clear it is apparant that when the brake "disengages" the anti-lock doesn't engage because the car slides. I have slide through a red light, onto a busy street. Fortunately there have not been cars in the vacinity. I have taken the car to the dealership 3 times for this problem with no solution or recommendation.

- La Crosse, WI, USA

2010 Toyota Prius, with 29000 miles. Pulling into a parking lot at a very slow speed, applied brakes to stop car, but it did not stop it, it started jerking forward, until it stopped when it struck a fence, injuries occured as a result, seat belt did not old back driver, and driver wipped forward and back striking steering wheel. Vehicle was towed to toyotta dealer. Still wating for Toyota Corp to advise of error that occured, data from cmputer has been downloaded by a private firm and delivered to Toyota. 8/9/11 accident occured on 7/25/11 at 14:30.

- Dartmouth, MA, USA

The contact owns a 2010 Toyota Prius. The vehicle was included in the recall under NHTSA campaign id number 10V039000 (service brakes, air:antilock:control unit/module) and had the repairs performed. The contact stated that after the repairs were performed, while driving approximately 15 mph over a uneven road surface, the brake pedal was depressed and the vehicle suddenly accelerated for a few moments. The contact also stated that the failure only occurred when driving over an uneven road surface. The vehicle was taken to an authorized dealer for diagnostics, where the technicians were unable to diagnose the failure. The vehicle was not repaired. The approximate failure mileage was 100. The VIN was not available. Had the recall done but it did not fix the problem. Toyota has been unresponsive and the dealers say there's nothing they can do. Updated 11/16/2011

- Providence, RI, USA

Ever since I purchased my 2010 Prius in November, 2009 the brakes have been a problem. When braking while driving over a bump or pothole the car looses braking ability and there is a surge of power. The dealership claims there is no problem and the recall work has not made a noticeable difference.

- Silver Spring, MD, USA

Brakes failed. 2010 Toyota Prius. 160,000 miles on vehicle. When I started the car, I had no brakes. When I put the car in gear, I then had brakes. I had brakes when I pulled up to a stop sign. As I waited for traffic I then had no brakes. When I began to move I had brakes, but then as I gained speed, the brakes went out. I managed to stop with the emergency brake. Checked the brake fluid: Completely full. Dealer said the master cylinder went bad. Orginal brakes on vehicle; not even half used. Highway miles on vehicle. Very hot day. I believe it is electrical, dealer says mechanical. Had there been an accident, this incident would be looked into. As it is, no dealer will look into a car that is out of warrenty. I complained for 5 months about the brakes when I first bought the car new. Dealer told me that there is nothing wrong with the brakes. Even after the recalls, there still is problems with the brakes. Now I believe there is a problem with the master cylinder, -the electric component part of it- but Toyota will only look into it when there is a serious accident.

- Des Moines, IA, USA

I am experiencing the same problem as many other 2010 Prius owners. The brakes fail briefly when driving over large potholes located on a grade. I have discussed the problem with a Toyota dealership and was told that they are aware of the problem but until a recall/solution is issued there is nothing that they can do. They told me to brake harder when driving over potholes to compensate for the problem; the brakes, however, do not fail with every pothole. It seems like the potholes have to be a certain size, yet from the driver's seat, it's extremely difficult to judge the size of the pothole and thus if the car will lose braking power. So, slamming on the brakes for every pothole is just as dangerous as not since stopping too quickly can cause a rear-end accident. I live in a city overwhelmed with hills and potholes so this problem happens nearly every time I drive the car. It has gotten to the point where I am fearful to drive my car since I have had several close calls and know that unless this problem is fixed, it will eventually cause an accident. Briefly losing braking power may seem insignificant but until you have actually driven the car and experienced the lack of control the only comparison that I can make is driving on ice. You feel utterly helpless for the time that the car is out of your control, even if it's only a few seconds, during which time you are legally and morally accountable for what your car does or hits. There are plenty of other road hazards and safety concerns, whether or not my car is going to stop when I apply the brakes should not be one of them. I implore you, please investigate this problem and require that Toyota take responsibility for fixing it and ensuring the safety of Prius owners, pedestrians and other drivers. Thank you.

- Pittsburgh, PA, USA

I was making a sharp right turn to pull into a parking space, slowing to a stop. The car suddenly and unexpectedly accelerated forward out of my control. I applied the brakes as hard as I could, with no response. As the car was racing into a tree, I shut off the engine by pushing the power button to off. The car knocked down a tree and came to a stop on top of it.

- Cotuit, MA, USA

Car stop on crowed warning appered on dash hybid over heating car stop. Had to restat car. By time pulled to shoulder warning light whent off. Car smelled of burning this happen on Friday on sat brough car to santa monica they had no answer. As needed more info had car towed on Monday left car till sat. Their diagnosis using gas and brake at same time how do you do this with one right foot?. you never drive with the left foot computoe is in error

- Los Angeles, CA, USA

The contact owns a 2010 Toyota Prius. The contact stated while driving at low speeds in inclement weather and trying to decelerate the vehicle would not stop moving and it crashed into the rear of another vehicle. There were no injuries from either vehicle. A police report was filed. The vehicle was not towed because it wasn't a major crash. The manufacturer was then contacted and they advised him that they were unaware of any failures in regards to the brakes. The failure mileage was approximately 65,000. Updated 08/31/2011

- Flint, MI, USA

The contact owns a 2010 Toyota Prius. The contact stated that the brakes were applied but the vehicle did not respond or slow down. The ABS warning light illuminated and the driver had to use the parking brake to stop. The vehicle was taken to an authorized dealer who replaced the master cylinder. The failure continued. The vehicle was taken back to the dealer where it was scheduled for a second repair. The VIN was unavailable. The current mileage was approximately 100,000 and the failure mileage was 97,000.

- Long Pond, PA, USA

The contact owns a 2010 Toyota Prius. The contact stated as he was pulling into a parking space, he crashed into a wall because of the brake pedal engaged. The contact stated the accelerator pedal and brake pedal was not positioned properly. The contact tried to stop the vehicle and his foot moved off of the accelerator and under the brake pedal. The manufacturer inspected the vehicle and stated the space between the accelerator and brake pedal meet their specifications. The failure and current mileages were 2,600. Updated 6/8/11 updated 06/15/11

- Redding, CT, USA

Sudden loss of braking while slowing down while going over a bump. Apparently the regenerative braking fails, and the car relies on only friction braking when going over a bump. This gives the feeling of brake failure and unintended acceleration, and the only way to prevent an accident is to push hard on the brakes. This happens consistently, and has since the car was new. The Toyota ABS ECU flash was performed, and made little or no difference.this is very disconcerting to say the least, and will lead to accidents. Toyota claims that this is the "normal" operation of the ABS system - in reality it has nothing to do with the loss of traction. Check out these data: priuschat.com/forums/gen-II-Prius-technical-discussion/93233-data-brake-loss-aka-sudden-acceleration-after-bump.html.

- Centerport, NY, USA

The contact owns a 2010 Toyota Prius. While the contact was driving approximately 10 mph, the brake pedal was engaged and the vehicle began to lurch forward unexpectedly. The failure recurred whenever driving in rainy weather conditions or bumpy and icy road surfaces. The vehicle was taken to an authorized dealer and repaired under NHTSA campaign id number: 10V039000 (service brakes, air:antilock:control unit/module). The recall remedy failed to correct the problem and the failure persisted after the repair. The failure mileage was approximately 1,000. The VIN was unavailable.

- Niles, IL, USA

I travel quite a bit these days and on my way home from coachella music festival, my brakes gave out. I mean to say, pushing the pedal all the way down, no resistance, no slowing, a completely limp pedal....until I repeatedly stomped on it and the car locked and skidded to a stop, feet away from the car in front of me. The brakes returned intermittently, so I took the right hand lane at 40mph and tested the brakes regularly until I got to my dealership. Scariest thing ive ever experienced. Ive had the car since August 09' and currently have 43K miles on it. I know thats a lot, and its unfortunately outside of my warranty now, but I wanted to log it here, as soon as I could. It started one day before the freeway incident, whenever I would depress the pedal, a loud high pitched squeak would come out. I didnt think much of it outside of "better get that looked at" but didnt notice any brake failure. The next morning, I turned on the car and every dashboard light came on and a fast consistant beeping went on for about 5 minutes, during which time the brake pedal had zero resistance. I sat there with a serious wtf look on my face, when out of nowhere, the dash lights went away, as did the beeping, and the car drove as normal with full regular brake pressure (besides the squeak). I received a call back from the dealership. They say it's going to be $3K for a master cylinder replacement and that Toyota corporate wouldn't aid in the cost, despite my hybrid warranty still covering the hybrid ECU (the master cylinder unit includes the ECU). [xxx] (my dealership service manager) said herself that it was not my fault and that the part is not repairable, "it either works, or it does not. It must be replaced". this could have been catastrophic, had I been any closer to the car in front of me. The failure of one part (which failed through no fault of the customer) rendering the brakes nearly useless is too scary not to report here. [xxx] information redacted pursuant to the Freedom Of Information Act (FOIA), 5 U

- Ca, CA, USA

Driving on a rain covered road and hit a rough spot in the road. Brakes did not engage at all for about 1 second. Was able to stop after that and just avoided rear ending a car at a stop sign.

- Concord, MA, USA

2010 Toyota Prius--inconsistant braking and varying brake pedal pressure requirements. When braking, brake pedal travel distance varies. At times no brake action after pedal has been partially depressed requiring more brake pressure to re-engage brakes. Sometimes occurs when gas engineswitches to electric or vice versa, other times inconsistent brake action occurs with either power source. Frankly you never know how the brakes will perform. Taken to dealer-I was told no problem found. They would not keep the car for days to continue tests. This is my fourth Prius and this vehicle has more problems and concerns than all the others combined.

- Cincinnati, OH, USA

I drive a 2010 Toyota Prius. In the last week I have noticed on several occasions that when braking when coming up to a traffic light, all of a sudden the pressure on the pedal decreases and the breaking power fades. Then in panic I start pumping the pedal which after a split second gets the brakes to kick in again. Luckily the car has so far then come to a halt before I hit the car in front of me. My Toyota dealer has dismissed my claim saying that they checked the car and the computer shows no error code. They told me that everything is fine basically dismissing my claims of a near crash. They say there is nothing they can do and if the computer shows no error everything must be fine. The first occurrence of this was on the same day when I had to brake very hard to avoid a crash. On that occasion the brakes worked fine but driving home the same night I had the first occurrence of the above described situation resulting in a near crash.

- Alpharetta, GA, USA

TL- the contact owns a 2010 Toyota Prius. The contact stated while attempting to brake the brake did not respond he had to increase the stopping distance he experienced the failure several times, but the failure occurred intermittently. The vehicle was taken to the dealer whom performed a diagnosed, but was unable to locate a failure code the vehicle was also test driven, but the failure could not be recreated. The manufacturer was contacted and advised to take the vehicle to local dealership. The vehicle has not been repaired. The failure and the current and the current mileage were 9,999.

- Short Hills , NJ, USA

The contact owns a 2010 Toyota Prius. The contact was braking from approximately 30 mph and approaching a traffic stop when the brakes failed. The contact veered off the road and crashed into a snow bank. The vehicle was towed to the dealer and the contact was advised that they would have to turn the vehicle over to the manufacturer and wait for a diagnostic on the vehicle. The vehicle was not repaired. The failure and current mileage was approximately 4,000.

- Yonkers, NY, USA

I purchased a new 2010 Toyota Prius (model 3) in late July 2010. In almost every respect, this car is wonderful. However, the car has consistently diminished (apparent) braking effectiveness when the brakes are applied and the car goes over a patch of rough road, pothole, etc. When the brakes are applied with a consistent pressure, the car "feels" as if the brakes disengage upon entering a rough patch of road. This happens every time. (for example, I notice it every time I slow down at my street corner where there is a long-standing patch of rough pavement.) since 1994 I have owned 7 cars with ABS (Honda, Nissan, and Toyota Camry), I have never experienced a similar sensation in any of these other cars. I have adapted my driving style to this anomaly, but I worry about my kids and friends who may occasionally drive my Prius. It is unnerving to apply the brakes and have them feel like they are disengaging when you enter a rough patch of road. Since this problem occurs consistently, I think it should be possible to test to see if this apparent braking anomaly is actually increasing stopping distances. (for example, test Prius vs. Model without apparent braking anomaly on smooth and rough roads to see if relative braking distances of Prius are more heavily affected by rough roads that comparison model.) P.S. after purchasing my new Prius, I noted that my dealer's service blog, had several reports of similar problems that were not corrected after servicing by the dealer. Some posts noted that the dealer had applied a software fix that Toyota distributed in early 2010. My car was manufactured after that fix.

- New York, NY, USA