While decelerating due to application of the brake pedal if the vehicle encounters a pothole or other deep road imperfection the braking cuts out and the vehicle resumes coasting immediately even though the brake pedal is depressed. Harder application of the brake pedal is necessary to resume vehicle braking. Subsequent braking power is much reduced compared to normal braking and significantly harder brake pedal pressure is necessary. Normal braking may be reestablished by lifting the food off the brake pedal completely and re-depressing the brake pedal. The severity of the sudden loss of braking (complete loss of braking) is shocking, alarming, and panic enducing and results in whiplash to the vehicle occupants as the passengers, being unconsciously braced for deceleration, are suddenly jolted back into their seats. When another vehicle is located in front of the vehicle the sudden loss of braking and subsequent weak braking power despite strong brake pedal depression is highly alarming. The most reproducible situation in which this happens is on dry pavement while exiting a highway and decelerating on a straight or slightly curved exit ramp with one or more potholes. The phenomenon occurs in other circumstances as well where a pothole is encountered while the vehicle is under braking.

- Norfolk, VA, USA

When applying the breaks before and over railroad tracks, the breaking will disengage and then reengage. It will also happen with pot holes. You get the feeling the car won't stop. This has been happing for year and the service department gives different answers to the cause.

- Indianapolis, IN, USA

I have had this problem ever since I bought this car used from a Toyota dealership. If I drive over an uneven surface, pothole, etc., my car will skip and then lurch forward. It is worst on wet roads. I have trouble stopping it. On snow I have little to no traction. I got a new set of tires and I wasted my money. No difference. I don't feel safe driving this vehicle. I have been driving for years, had many different vehicles, drive as part of my job, and have never experienced anything like it. Contacting Toyota about it was a waste of time. I have spoken to other Prius 2010 owners and every one says the same thing about how it handles when going over bumps. The skip and lurch could easily result in a rear end collision. I think this is something Toyota just doesn't want to admit to as being a problem.

- Barto, PA, USA

Car seems to lurch forward before stopping when braking on a rough surface. This is an ongoing problem. Despite NHTSA notice that there is a software fix available for some 2010 priuses, Toyota maintains my car is not included in the batch that was to receive them. Update 9/15/15 updated 12/06/2017

- Oakton, VA, USA

As many previous owners described, I am also having problems with the brakes at low speed since the beginning of owning this vehicle (October 2009). Dealer couldn't replicate the problem. Although the car went through the recall for the break system is still having the same issue ever since. The other issue with the brakes happens after rain. It makes a screeching noise without performance being effected. It goes away usually within a half an hour. This has been an ongoing thing too for few years by now. The other issue I had as well as others is dimming of lights that has been occurring since last year. We needed to switch the lightbulbs more frequently than seems normal. Didn't even think it was out of the ordinary until I read the comments here about it. The other problem I started to have is with a stereo display system and the voice activation for the bluetooth. The display had some weird lines on it after a very cold or a very hot day (radio was working fine just the display was not working properly). Eventually goes back to normal but this started happening the last year or so. The same time also had a problem with the voice activation unit which turned on unexpectedly and turned back on in 10 seconds after each time I turned it off. This was happening for a good 30 min at that time. This only occurred twice but both times was after a hot day last summer. This year so far haven't happened yet.

- Brooklyn, NY, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving at 20 mph, the contact drove over a pothole and the vehicle veered to the right. In addition, the vehicle accelerated in excess. The failure recurred on numerous occasions. The vehicle was taken to a dealer, who was unable to diagnose or repair the vehicle. The manufacturer was notified of the failure. The contact was aware of NHTSA campaign number: 10V039000 (service brakes, air). The failure mileage was 15,000.

- Olney , MD, USA

We have experienced inconsistent break feel after ABS actuation during slow and steady application of the brakes on rough or slick road surfaces. We noticed also that there was a recall on this issue in 2010 but our particular car (by VIN number) did not qualify. We think that the recall should have included a broader sample of same year and model. We have brought the problem to the attention of the dealership several times but they have dismissed it as normal operation of brakes. We feel very unsafe in the vehicle.

- New Orleans, LA, USA

The contact owns a 2010 Toyota Prius. While driving 10 mph, the brake pedal was depressed and failed to respond. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The approximate failure mileage was 56,000.

- Dublin , CA, USA

I read the complaints & found one listed recently dated 5/22/15 that describes the exact problem I have. My Prius is a 2010 purchased in 7/09 & shortly thereafter, I noticed the braking issue. The following info in quotes is copied from the other complaint which is the same issue I have - (other complaint stated) "when you are at lower speeds and hit a pothole or big bump while breaking, there's a sudden 'jolt' and it feels as if the breaks have been completely released momentarily. It almost feels as if the car lurches forward. I feel it heightens the chance of a crash due to increased deceleration time." It sometimes feels like you are sliding on ice & have no control over the car. (and it is scary when it happens!) I had Toyota check my vehicle a few times, but they were not able to duplicate the problem, so nothing was fixed. I thought it was just my car this was happening to. Now I find that I am not alone in this. The complaint I referenced stated that there was and a "previous investigation & partial recall but it didn't affect all of the 2010 production vehicles, just a portion." I never heard about any recall or investigation on this. I agree with the other complaint that "this needs to be re-investigated as my car and countless other cars (both involved and not involved in the last recall) are (still) malfunctioning when it comes to the breaking system at slower speeds when on rough roads / encountering potholes / bumps." My car still has this problem even as it is now 5 years old. What needs to be done to correct this issue?

- Florence, KY, USA

Experience inconsistent brake feel after ABS actuation during slow and steady application of the brakes on rough or slick road surfaces. Stopping distances increase.

- Hillsborough, NJ, USA

I have owned two Prius and both of them have had the same breaking issue. When you are at lower speeds and hit a pothole or big bump while breaking, there's a sudden 'jolt' and it feels as if the breaks have been completely released momentarily. It almost feels as the car lurches forward. I try to avoid potholes, etc anyways, but I am extra vigilant because of this issue as I feel it heightens the chance of a crash due to increased deceleration time. Last night, I was coming up to an intersection that had a yield sign. The car in-front of me stopped. I hit my breaks, but while breaking, I hit a pothole (it as dark so I couldn't see it) my breaks suddenly behaved as described above - they let go for a moment and the car somewhat jolted forward. I was unable to stop in-time and rear-ended the driver ahead of me. I was always afraid that because of this breaking issue that this would happen - and now it has. I know there was a previous investigation and a partial recall but it didn't affect all of the 2010 production vehicles, just a portion. I feel this needs to be re-investigated as my car and countless other cars (both involved and not involved in the last recall) are (still) malfunctioning when it comes to the breaking system at slower speeds when on rough roads / encountering potholes / bumps.

- Arlington, TX, USA

Have owned the car since new in 2010. Brakes exhibit the same issue mentioned in other complaints I.e. when going over bumpy roads, brakes "release" and re-engage causing the car to not stop quickly. Had software recall done but did not significantly affect. Have just been living with it but after seeing all other complaints, thought I would weigh in with the same problem as it appears to be a common issue with a design flaw of some sort that needs to be addressed for safety reasons.

- Charlotte, NC, USA

Car came out of the car wash and as I got ready to pull out the brake light came on and there was a rapid beep. Pushed on the brakes and felt no resistance like brakes did not exist. Had the car towed to the dealer (right Toyota on frank lloyd - scottsdale AZ) - dealer ran a software to fix it (part of a recall) but that did not fi X the issue. Dealer asked me to have hydro booster pump and the assembly replaced - they charged me $4200 for parts and labor. I was forced to pay as they said they tried to fix it throught he software but it did not. I feel that Toyota is repsonsible for the system failure - the brakes are critical - they suddenly stoped working. It could have been fatal if I was on the road when it happened. The failure should be gradual and there should be a certain warning if the pump was malfunctioning. I need your help in resolving this. Toyota should be responsibelf ro paying the invoice.

- Fountain Hills , AZ, USA

I have notice a definite release in braking action when my 2010 Prius goes over a patch of bumpy road, within 1 minute of leaving my home and going down the block. I experience this "release" of braking as a sudden brief acceleration that occurs while there is pressure on the brake pedal to slow down while going over the bumpy patch of road ( a 20 foot stretch of road with numerous shallow potholes). I bough this car used in September 2013. (it had 80,000 miles on it and a history of travel over gravel roads). On March 20, 2014, the local dealer did the E0E recall repair on the motor generator ECU and the power management ECU, to correct issues related to hard acceleration. At the same time, the dealer did the older Toyota recall repair on the brake pressure accumulator issue. I have not noticed this braking release issue later in the day. It seems to be most noticeable first thing in the morning, in the first minute or two of driving.

- Cedar Rapids, IA, USA

I had just pulled into the garage and was at a complete stop when the car surged forward and slammed into to the back of the garage, I would tip overattempted to stop the car with the brakes and they were not working so I shifted the car to reverse and it speed out of the garage up an embankment into a fence. It. was up on it's side and I was afraid that it would tip over so in an attempt to bring it down level I shifted to drive and it speed off forward it then jumped a row of bushes into the front yard and did a large circle in the front yard missing three large pine trees and hitting a small tree that ended up stopping the car and deployed the air bag.

- Evans , GA, USA

The Toyota dealer diagnosed a brake master cylinder and booster failure on our 2010 Prius at 27892 miles. Toyota declined to extend the brake recall that covered 2010 cars with a production date before November 2009. Our car has a March 2010 production date. Clearly Toyota was assembling cars with faulty brake master cylinders and boosters and they should extend the recall to cover those cars. The cost of the repair was $2760.

- Halfway, OR, USA

As I was coming to a complete stop at an intersection, the car jolted as if I was hit from behind and the brakes lost pressure resulting in me having to press the pedal all the way down to the floor. The brakes would not respond and I had to put the car in park to get it to stop. The same thing happened after I first got the vehicle in 2010. In Sept. 2010, the brakes did not respond, causing me to slide into the row and resulting in an accident. The car will also jolt when the brakes are pressed while driving over a pothole or bump. I took the vehicle in to have this check on 4/2/15 at Toyota of lewisville, in lewisville, tx. They claim that everything checks out fine on the brakes and they can not get it to replicate the jolt or pressure failure. Per Toyota of lewisville, the car did have a recall for the brakes, which was repaired at Toyota of irving, but the brakes are still exhibiting problems.

- Flower Mound, TX, USA

This brake problems has occurred many times. During application of the brakes at low speeds on rough road surfaces the car suddenly loses braking power for a brief time then starts to work again if the brake pedal remains depressed. This has almost caused accidents a number of times and is quite frightening. The car was brought in for the recall and safercar.gov states that there are no open recalls. When we bring this to the attention of the Toyota dealer we are told this problem is "normal" and there is nothing more they can do. (however, I understand that they fixed it in the next model year.) in my opinion this is an unsafe condition and it has been complained about online by other Prius owners. I ask the NHTSA to require Toyota to fix this in the name of safety.

- Newton, MA, USA

The contact owns a 2010 Toyota Prius. While driving at approximately 5 mph, the braking ability seized and the ABS warning light illuminated. The contact came to a complete stop and the vehicle had to be restarted. The vehicle was driven to the dealer who stated that the hydraulic system failed. The hydraulic master cylinder had to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 27,000.

- Halfway, OR, USA

It was raining and I was existing the I5 Ram, when I bumped the brake, the vehicle speeded up more, I continue to pump the brake, then the vehicle started drifting, then I tried correcting, but it didn't work, the vehicle kept on driving, for about 15 seconds come to stop by the wall of the I5, it then bounced vehicle backwards and finally the vehicle come to stop after the shift broke, causeing a totally crash, meaning, no matter how hared I step on the brake, it didn't stop, it felt like there was no brake system. I only bought the car for 6 days earlier, and it was my third time driving it. I have been a drive for 7 years and I have never had any incident.

- Des Moines, WA, USA