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Toyota Prius Brake Problems



  • PF_FlyerPF_Flyer Member Posts: 9,372
    700 milliseconds IS significant if you ask me. At at just 20 mph, a speed you might be going in close proximity to a car in from of you, that 7/10ths of a second translates to 20 feet before a car would begin to stop.
  • wwestwwest Member Posts: 10,706
    edited June 2010
    Where did you get this number/limit...?

    My understanding is that the non-braking time is random, possibly infinite, due to a design flaw within the firmware.

    But yes, even 100 milliseconds of absolutely no braking can not only be extremely frightening but easily result in an accident. In the past ten or more years I have been involved in two "light" rear enders due to needless ABS activation that inadvertently extended my stopping distance on a perfectly dry highly tractive surface.

    In my opinion ABS should NEVER activate unless VSC indicates a need for stearage, either the vehicle is not following the driver's stearing inputs, plowing, or is over-stearing.
  • PF_FlyerPF_Flyer Member Posts: 9,372
    We just bought our first vehicle that came with ABS standard. Only about 1,500 miles so far so I haven't run into any situations where I've noticed any difference yet. Hopefully I never will ;)
  • john1701ajohn1701a Member Posts: 1,897
    You'd have to be braking fairly hard only using regen, strike a large pothole, and be approaching a vehicle already at a dead stop 20 feet from there. Could happen. Highly unlikely though. And probably never after getting the update.
  • wwestwwest Member Posts: 10,706
    edited June 2010
    "...You'd have to be braking fairly hard only using regen..."

    No, the lurch/surge occurs as the result of the need to transition to ONLY frictional braking from LIGHT regen braking or (typically) heavier combined regen/frictional braking. ABS is ONLY implemented on the frictional brakes.

    "..large pothole.."

    No, any small perturbation or slippery spot in the roadbed that results in a regen braking tire's loss of contact/traction, even momentarily. Loss of traction sampling, calculation, is done, typically, every 10 milliseconds, 100 times/second.

    "..Highly unlikely though..."

    Actually, more likely than otherwise if you drive any hybrid on a regular basis.

    "..and probably never after getting the update..."

    Wrong. The lurch/surge forward is systemic to ALL Toyota HSD hybrid vehicles and cross-licensed "clones". The service campaign only addresses the firmware flaw that tended to elongate the low or even non-braking time during this ABS induced transition period.
  • wwestwwest Member Posts: 10,706
    The first ABS equipped vehicle we owned was a 92 Jeep Cherokee Limited. I always removed the ABS pumpmotor fuse during the summer months when loss of stearage control due to heavy braking was less likely to occur.

    Unless you need to input directional control or corrections during the "event" all ABS activation does is elongate your stopping distance.
  • sas9sas9 Member Posts: 28
    While I can't tell you to drive and enjoy your car, I can say that my 2010 Prius is a dream. I've experienced a slight breaking delay when going thru a pothole or over a severe bump. I keep my foot on the break and after a second or two the delay is over.

    When I got the car, I was concerned about this and just stayed far enough away from the car in front of me so I would feel comfortable. Now, I don't even do that as I've gotten used to the slight delay and am not really concerned.
  • betsyrbetsyr Member Posts: 5
    I finally gave up and traded it in. The final straw was when we took it to the dealer and they told me that the computer showed that in just over a month I had been driving almost 200 times pushing both the gas and the brake. The head of the service told me that while it was an odd reading (we had had a few readings like this on previous checks), he could not argue with the computer. I can tell you that I have NEVER driven while pushing the gas and brake simultaneously. I was informed that there was no other testing for them to do and I was basically stuck with a car that I did not trust and obviously had a serious computer problem.

    Although we lost 12k, we traded it in and I have never regretted it. We were afraid that if I did have an accident, Toyota could simply point to the data in their computer saying that I was driving two footed and the blame would be squarely on me.
  • wwestwwest Member Posts: 10,706
    Did the dealer check to see if the brake pedal position microswitch was out of position and would sometimes be actuatd even with no braking..?
  • agnostoagnosto Member Posts: 207
    edited August 2010
    Almost 3500 miles with my 2010 Prius IV with NAV without any issue and averaging over 70MPG computer calculated... In conclusion, as I have stated before, not many people really know how to drive a hybrid vehicle effectively, realizing that when I tell them I get over 70MPG (with moderate up/down hills) and they are surprised...
  • betsyrbetsyr Member Posts: 5
    I was getting incredible gas mileage and at the time I lived in a very hilly city. That was not the problem.

    The problem was the brake issue. To the person who asked if they checked a particular thing on my brakes. I honestly don't know. They kept the car for a day and assured me that they had checked every single thing on the brakes (to include the pedal) when they saw that I had supposedly been driving almost 200 times using both the gas and brake. Unfortunately I was a few days out from a cross-country move for my company and did not trust loading my young children in the back seat for a 2000 mile drive.

    For me the most logical choice was to sell and cut my losses. I do wonder if other people are having the same type reading saying they are hitting both pedals at once.
  • mission1mission1 Member Posts: 2
    I have the same problem with my 2010 Prius. It seems to happen more when the weather gets colder. I had the computer "fix" done at the dealer, but it didn't fix it. I bought my car last Dec. & slid through 3 intersections in snowy weather. I'm a very good winter driver, but when brakes release, even for a second or two, when you are stopping on snow covered roads, the car lunges and skids. I start stopping three blocks ahead in snow now because I'm not sure when it will lunge forward.
    This is dangerous. I think people in California won't understand because they won't drive in these conditions. I can see where a tight turn on a gravel road would be hazardous with this braking problem as well.
    The dealer tells me the brakes releasing for a second isn't a problem and I should learn how to drive with it. At first they act like they don't know what I'm talking about. They know very well what the problem is and the computer flash doesn't fix it. I hope you reported your accident to the NHTSB. I hope everyone does! This is dangerous.
  • mission1mission1 Member Posts: 2
    The problem with the brakes releasing is actually happening quite regularly. I'm noticing it more now as the air gets colder. I think some kind of sensor may be involved. I agree about the danger in driving a car with this problem. I wouldn't let my sister borrow my new 2010 Prius because this might happen. It may not be a problem in warmer climates, but in the Northeast it is huge. You don't want your brakes releasing while coming to a stop at a snowy intersection - this happened to me several times- because you'll slide through the intersection (and so I did!). I'm a very good winter driver and couldn't understand what was happening until I realized it was the brakes releasing for a second, causing the car to lunge forward. I encourage everyone with this problem to report it to the NHTSB. The "flash" fix provided by the dealer does not fix this problem & I was told by the dealer that I have to live to drive with it. This is outrageous! I waited 3 years to buy my 2010 Prius & I am sick about this and I am not going away until they fix my car!
  • masterpandamasterpanda Member Posts: 19
    These messages have focused me on seasonal sense of dread about facing the second winter with my 2010 (in the Wash DC area, where at one point last Feb we had three feet of snow on the ground and few have decent winter driving skills). I agree the flash fix did not resolve the issue. On the other hand, I grew into getting used to it and did not take a "lunge" in a bad place like a snowy intersection. I probably need to steel myself to get back into robotically compensating for this problem.

    RELATED PROBLEM--This is related only insofar as it concerns what happens when you depress the brake pedal. Every once in awhile another driver tells me my brake lights come on late. Where I can see the red glow from my own brake lights reflecting off a surface visible in my rearview mirror, I occasionally get the same feeling. No need to describe how dangerous late brake lights can be, especially with the endemic tailgating at any speed on the roads where I am. Does this sound familiar? Can it be fixed by a dealer?
  • wwestwwest Member Posts: 10,706
    Have you not driven a FWD vehicle on an adverse condition, slippery, roadbed previously...??

    But to be fair I have had EXACTLY the same instance you describe in a '92 Jeep cherokee Limited. On a truly slippery surface the Jeeps ABS system will become so active that you literally cannot bring the vehicle to a full stop.

    The conditions you describe are exactly the reason FWD vehicles are so hazardous for wintertime use. Now here you are in a vehicle with tires specifically desired for low rolling resistance....LOW TRACTION coefficient except on a reasonably tractive surface.

    Next time try careful/judious use of the rear implemented e-brake, parking brake.
  • wwestwwest Member Posts: 10,706

    The rear brake light switch, control, is an integral, KEY component of your hybrid's braking system. If the brake lights are not coming on the very INSTANT you touch the brake pedal, even lightly, the regen/frictional braking system will not operate as designed.
  • dan19dan19 Member Posts: 10
    Just bought a 2010 Prius V with the Technology Package. Bought from a Ga dealer 200 miles away. On my trip home to TN, on two occasions, while traveling 70 mph, dynamic radar cruise control on, lane keep assist on, the vehicle suddenly braked. Both times I was passing a semi-tractor/trailer rig on a slight right curve. I understand how the pre-collision avoidance system could be a cause if I was on a sharp left turn. But this was on a slight right curve. I'm taking it to a dealership today. Has anyone else had this issue? I know there aren't many Priuses with the Tech Package. I'm confident that one of these tech features failed to operate as intended.
  • bandorganbandorgan Member Posts: 1
    I believe that bleeding the brakes can correct the Prius brake grabbing / failure problem. I believe bleeding of the brakes, flushes air of foreign material out of the “Brake Actuator” module.

    Some background;

    I have a 2004 Prius that we bought new.

    At about 90,000 miles the brakes would grab at low speed (less than 5 MPH) when backing out of the garage or coming to a stop. This was a intermittent problem which could not be reproduced at the dealer, and the dealer could find no problem with the brakes. There were no alarm light on the instrument panel.

    At about 100,000 miles the car developed a second brake problem, in that at higher speeds (about 30 to 50 MPH) when braking, the brakes would suddenly fade for a second and then grab, this would repeat it self, bringing the car to a very jerky stop. There was no alarm lights, and this was not an ABS stop. The dealer could got find any problem with the brakes.

    At about 112,000 miles the higher speed braking event happened twice with in a month. I took it back to the dealer and they did a 100% inspection of the brakes and could find no problem. As part of this inspection they bleed the brakes. I have now driven the car for over 3 months and greater than 1,000 miles, and have had no problems with the brakes.
  • whitey9whitey9 Member Posts: 138
    Bleeding the brakes prolly did not do any good. If there was air in the system previously, you would have noticed it when stopping. Pumping the brakes would have been required, and a "low" pedal would have been present.
  • cgollihercgolliher Member Posts: 16
    Thanks for the info. My 2010 Prius is JUNK!!!!! I wish someone would steal it and I would never have to see the car again! Paid way too much for it, can't sell it now that it has been wrecked. Continue to feel like my car is very slow to respond if/when urgent braking is needed. The braking system on this car is unsafe.
  • roxanesroxanes Member Posts: 1
    Have been searching for someone who has the same problem I do.
    My 2010 Prius has performed well, but a new wrinkle started last year. While going down hill on the 405 freeway, the gas pedal did not engage. I coasted down, pulled over, turned off the engine, restarted and was on my way.
    It has happened 3 more times.
    I took it to the dealer and they tell me that it is driver error-that I am putting on the gas and the brake pedal at the same time. That is physically impossible and I have never driven with 2 feet! They have referred me to customer relations- their response so far is for me to go to the dealers so they can test drive. Seeing how this has happened only 4 times in over a year, the dealer would be driving forever.
    In any case, their ‘diagnostic’ tools spotted this error, but they say there is nothing wrong with the car; it is my driving.
    Customer service has not returned my calls for the last 2 days.
    Is there hope for this sad story?
  • betsyrbetsyr Member Posts: 5
  • betsyrbetsyr Member Posts: 5
    I finally gave up and traded my car in. We took a huge loss, but we considered the liability to be greater. Had I had a wreck in it with the computer reading that I constantly driving 2 footed, I would have taken the blame. No matter how many times I assured them that I was not driving with 2 feet, they did not believe me. They told me the computer was correct thereby removing all blame from Toyota.

    I tried the customer relations, but got nowhere. All they will tell you is that you need to take it to the dealer.

    I hope you get some resolution. I miss my Prius, but I don't miss the worry that it brought about.
  • ivgivg Member Posts: 1
    Prius 2009.
    Came home on January 29- no problems.
    Next morning- high pitch system whistle; ABS, brakes and VSC lights are "on" and brakes are working terribly.
    Went to the Toyota dealer- they told me that they never heard about a problem like this before and wanted me to pay $180 just for inspecting the car. I did not trust "never heard about a problem like this before" talk and went to an electric specialist. After the computer reset my car, it was working normally again.
    Up to this point really liked the car. Hopefully it will work properly from now on.
  • regman17regman17 Member Posts: 2
    For those of you that don't know, Toyota changed the brake system for the 2010 model year to a completely new design. You can't compare it with previous model years as the system works differently. I have driven the 2010 Prius before and after the software "fix" and agree the problem was not fixed. I also think it is interesting that there are over 800 brake related complaints filed at NHTSA for the 2010 (over 600 after the software recall) and yet there are 0 complaints for the 2011 model year. Obviously, Toyota knew there was a problem and fixed it with the 2011 model year. With all the customer complaints, I don't understand why NHTSA has not taken action. Maybe a class action lawsuit is needed.
  • kingrob84kingrob84 Member Posts: 2
    I read that they redesigned the braking systems for the 2010 Prius. That appears to be Toyota's response to the fact that the U.S. Generation 2 Prius (2004-2009) has had low-speed brake failures reported to the National Highway Traffic Safety Administration (NHTSA) at 31 times the rate of such failures reported for the 2004-2009 Corolla, which of course has traditional brakes. reliable cars
  • masterpandamasterpanda Member Posts: 19
    So....what's your point? The Prius 2010's alleged brake failures are well known in reports, but not proven by any skeptic or compromised party to be "electronic" or software.

    And then there was the software patch for 2010's "surge" issue that does not work for me or many others.

    The interesting thing would be if the "Prius 2011" brakes are any different than the 2010s.
  • regman17regman17 Member Posts: 2
    The basic design of the 2011 brake system is the same but you don't know what they may have done internally to the parts or software. The Toyota service part number for the 2011 is different than the 2010.
  • 625k_inc625k_inc Member Posts: 5
    edited February 2011
    How do you recreate this brake problem? ... speed, road surface, weather, braking force (heavy, medium, light)

    It took over a month of trying before I was able to recreate the original brake pause. After the flash, I was unable to recreate it. This doesn't mean the flash cured all brake problems so I'd like to try and recreate any current symptoms.

    Bob Wilson
  • lovedove41lovedove41 Member Posts: 3
    edited June 2012
    I am currently in the process of arbitration process with Toyota, concerning my 2010 Prius. It has been fixed during that recall, but the problem is still occurring. Has anyone actually been through this process with them and can share with me? The main issue is the break problems and acceleration. I have since taken it in and they can find no problems. If anyone reads this and has advise about how to process in the arbitration process with Toyota, please contact me or reply to this. I have a few questions about the process. I will write more about my specific problems soon, also. Any help would be greatly appreciated :cry: :confuse:
  • michaelroymichaelroy Member Posts: 4
    I went through New York's Lemon Law arbitration back in 2010 shortly after the recall and lost my case, primarily due to the arbitrator who was completely incompetent. I too had my car "fixed" but still experience the braking issue when I brake over a bump, manhole cover, etc. It's hard to replicate, especially during an arbitration case. I would check out the latest information on this issue on the NHTSA Web site to see what others have continued to report on this issue. But I would say it's going to be a longshot to win your arbitration despite your continued concern about the safety. What I have come to learn is that most cars have recallable issues and it's just a matter of how well a company addresses it.
  • cgollihercgolliher Member Posts: 16
    I was lucky, I guess! A few months after getting my Prius fixed after my off road event, a huge 4x4 pick up ran right over the little car. The driver never even saw me sitting behind him. The car was totaled, and I was okay except for a few bumps and bruises. I am just thankful to be rid of that car and to still be alive. It was a "death trap!". Good luck! My insurance company is still involved in a suit against Toyota! Go out and buy
    an American made car! Support your country and be safe!
  • whitey9whitey9 Member Posts: 138
    The car is obviously NOT a "death trap" since you obviously SURVIVED!
  • whitey9whitey9 Member Posts: 138
    Please learn how to correctly spell "brake'. It will lend to your credibility.
  • lovedove41lovedove41 Member Posts: 3
    edited June 2012
    ...I just paid off my car. If I had any money right now to spend on another new car or rental to drive, then there would be more options. ....I kind of bought a Toyota Prius (new) because I thought it was safe and would keep me safe. That is not what has happened in this case and the car should have had no problem to begin with. At least, I thought I was buying a good car from a good company. This also was not the case.
  • lovedove41lovedove41 Member Posts: 3
    Is is strange that they were the ones who wanted to start this whole arbitration process? They were the ones who mentioned it first and the conversation prior to that wasn't about going to court at all??
  • cgollihercgolliher Member Posts: 16
    Well Whitey, I consider that car a "death trap" because the braking system was the worst I have ever driven and I always felt like I was on the verge of not stopping and at any moment being at high risk for being involved in a collision that could end my life. I NEVER allowed either of my teens to drive the car because of this fact. So please don't tell me what my car was or was not. You would certainly feel like an jerk if someone out there today or tomorrow in the same car exp brake malfunction and dies as a result.
  • ks2010priusks2010prius Member Posts: 5
    I have a 2010 Prius IV and with the exception of the brakes it has been a safe and reliable car. I have not had any problems with unexpected/unprovoked acceleration. The cruise control has performed flawlessly. I have had problems with the brakes under certain conditions but not near as bad as some of the reports I have read. I tend to believe some of these are exaggerated.
    I first noticed a braking problem the first winter after I purchased the car, in Nov 2010. During a soft stop when one wheel went over a pothole or drop in pavement, such as after a bridge where the asphalt was lower than the concrete on the bridge, the brakes would fail for a split second. This happened sometimes when I slowed down before a stop sign or stop light and hit a pothole with one tire. It also happened if I braked when one front wheel was on pavement and the other passed over a patch of ice. In these cases would lose brakes for about for about 6 feet, then they'd catch. I took the car in and the dealer couldn't find any problems. After it happened several more times that winter I took it back again. They said there was a software update that should correct the problem. It didn't. Sometimes the brakes fail, for a short distance, under the same circumstances. It has never occurred during a hard stop, only during a soft stop and under 30mph. I believe it has to do with the regenerative braking and ABS systems not working together properly. I've learned to live with it and always leave plenty of stopping distance, and avoid potholes when I come to a stop.
  • biomanbioman Member Posts: 172
    I too own a 2010 Prius 4 and I too went through a similar process of learning to live with the switchover from regenerative barking to ABS. It is not a "flaw" it is the way the systems are designed, to date. Toyota is not the only manufacturer using a similar regenerative-ABS barking system. The other manufacturer's hybrids are experiencing a similar barking response during the switchover. So I've taught myself and my wife how to respond when barking systems causes that moment of "anxiety". We still have faith in the car and we are still happy we made the move over to the Prius. We have over 42K miles of low maintenance costs and no problems except for adjusting to driving a hybrid vehicle.
  • lily2012lily2012 Member Posts: 2
    I have a 2010 Prius, about 26500 miles. Just two weeks ago, I experienced very bad accident by unintended acceleration. I was backing this Prius slowly towards the left direction ( I needed to go to right direction) in a flat and dry surface, my foot was on brake--like we all do when we are backing. All the sudden, it started accelerating, in a few seconds, it turned >360 degree clockwise. I then passed out because of the fast turning and because I was so scared. The car kept going wild, passed two curbs and hit a truck backward and bounced back, then stopped by itself—because two tires on driver side got exploded when the car passed two curbs.

    Fortunately, no one was in the truck. Since the tires go flat before it hit the truck, I guess it was not as fast as it began accelerating, so I didn’t get injured.

    The local Toyota collision center checked the car and told me there was no problem with brake and gas paddle. They didn’t believe me and said they never heard of Prius unintended acceleration problem.

    Insurance said it’s my fault.

    I claimed the problem to Toyota. They said we can inspect your car, but it will take up to 3 months. And I need to pay the parking fee in the collision center. Is this crazy? Anyone has a suggestion as what I need to do? Thanks a lot!
  • imidazol97imidazol97 Member Posts: 26,791
    >hen I need to stop my car, i just push DOWN on the brake pedal. I do not ride around in circles tying to see how much damage I can inflict.

    Your statement that the poster tried to see how much damage he/she could do as a result of the quick movement of the car sounds like you are saying the poster intentionally did this? I disagree.

    You weren't there.

    >When I need to stop my car, i just push DOWN on the brake pedal.

    That didn't work for several people who claim their toyota products had runaway acceleration in the forward mode. Despite the floormats, sticky accelerator pedal sensor unit, and the use of NASA to supposedly rule out ALL electronic malfunctions of the drive-by-wire of the nonhybrid toyotas, I don't believe it is all solved.

    I read that this poster had something unexpected happen in reverse and that caused the driver to lose control. It seems as if the spinning or surprise caused them to faint or become uncapable of trying further to control the car. I accept that. Our concern is did the car do something unexpected, not was the poster trying to do as much damage as possible.

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • ks2010priusks2010prius Member Posts: 5
    I have to agree with the other post questioning the validity of your incident. It sounds like you were high, or low, on something. I doubt that a Prius turning circles, frontwards or backwards, can turn enough Gs to make one pass out. Why didn't you turn of the car off, try placing it in park or forward, or press on the parking brake. Since you didn't mention this I have to think you are not telling the whole story. If you are telling the truth then turn your car over to Toyota and have them extract the data from the on-board computer to see what really happened. I'm sure insurance claims agents have heard it all.

    I've had my 2010 Prius for 45,000 miles and it's been a superb car, saving me a LOT on gas. It's one of the few cars that delivers the MPG they advertise.
  • lily2012lily2012 Member Posts: 2
    I was trying to stop the prius when i saw a car coming on my way. My foot was on brake. But the car itself suddenly accelrated, and turning >360 degree backward in a few seconds. I can't control the car when the car was going crazy like this. I was very scared that I passed out. I am a female, never had experienced such a terrible situation.

    I found a website describing the unintended accelration in two situations: low speed and high speed. "low speed" refers to when we are parking or or backing up or trying to change a parking position when the car accelerates by itself; "high speed" means when we are driving it froward in relatively high speed. My case is the "low speed" one.

    I contacted Toyota. They will take the EDR (Event Data Recorder) to analyse--it will tak up to 3 months for them to do it! But I am afraid they will conclude that I stepped on both Brake and Gas paddle at the same time, like some posters said.

    I was pround of my Prius before the accident. I told a lot of coworkers how fuel efficient it iwas. Some of them brought Prius recently, some of them were planning to buy. But now I am much more concerned of safety than saving gas. When they heard of this accident (some of them saw it), a lot of them don't want to go with Prius.
  • markgreenmarkgreen Member Posts: 1
    Apparently those "extraordinary set of circumstances" happened to a large enough number of people that the manufacturer decided that a fix was needed.

    From the article:
    A Toyota spokesman said the Prius braking problem is caused by a computer glitch which creates a lag in response between the regenerative braking system (which captures energy during braking to improve fuel economy) and the antilock brakes (which help the car continue to steer under emergency braking situations). The problem occurs when the brakes are applied while the car is traveling over bumpy surfaces or in wet conditions.
  • bigteejbigteej Member Posts: 1
    I bought a 2011 Prius in March 2012. I thought all the issues with the brakes were taken care of back in 2009 and honestly thought it was all just people trying to get rich. My car has the brake hesitation problem, dealer can find nothing wrong and the dealer said that I was the first person to bring up this complaint. I believed them and thought I had a lemon or that maybe I was just a little jumpy about my brakes. The problem has been happening more and more. I decided to do a little research and I was immediately outraged to learn that this has been an issues with these cars for years and 1000's are reporting it. Dealership doesn't know whats wrong still and that car has developed other electronic issues such as the smart key system malfunctioning and the security system not letting me lock the car. I have a 6 month old car with 10K miles on it and its the first new car I have ever bought but I'm scared to drive it.
  • glenda7glenda7 Member Posts: 1
    I have this car for a year now and still experiencing sudden acceleration at times when I slightly press the brakes and the car hits a small bump or pot hole, it accelerates. I almost hit a pedestrian in two incidences, and many times almost rear ended other cars. I complained to my dealer but they said they did not find anything wrong with my car. They have emailed an engineer from California about it. It's been a month and I did not hear from them yet. Does anyone have a solution about this matter? I do not want to get into a car accident or hit a pedestrian....
  • wwestwwest Member Posts: 10,706
    What you are experiencing is the "delay" in the transition from regenerative, FRONT wheel ONLY, braking, to frictional braking ONLY, braking on all 4 wheels. Not that the addition of rear braking makes much difference in most cases.

    Obviously the car "wants" to use regen braking, especially so if the HV battery charge is close to being marginal. regen braking only occurs on the front know, the one's you constantly rely on for directional control.

    So any, even the smallest, indication of front wheel slip during braking will be, MUST BE, reacted to instantly. So, would you like to have, with definity, a sudded increase in braking rate, or a "slow" transition into a less pronounced braking mode...?

    There is a serious level of MG mass inertia to be ovecome inside the PSD/CVT in switching from "brake" to "neutral". The multiphase rotating electric field(s) inside the MGs cannot "lead" the rotor by too great a margin without the possibly of becoming unlocked.

    And you DO NOT want the frictional braking to come online until most of the regen braking has been abated.

    Drive the new RWD Infinity to get an idea of the overall driving dynamics of a RWD hybrid vs a FWD.

    Hard call for the design engineers.

    An ideal solution overall would be ofr the Prius to become a RWD hybrid.
  • wwestwwest Member Posts: 10,706
    "..sudden acceleration..."

    More like "lurch forward" as the regen braking is released, "wound down", during the transition to frictional braking, with all wheel "distributed" FRICTIONAL braking and ABS capability.

    Regen braking can be PERFECTLY "metered", fine resolution modulation, moderation, while frictional braking simply cannot be. So Toyota dare not bring on frictional braking until regen braking is mostly "wound down", the PSD has gone from regen mode (reverse[?]) to "neutral"

    The only solution I can think of is to ALWAYS brake EARLY and HARD, only lighten the braking once you have slowed to your comfort level with DEFINITY. Always "coast" up to a final stop.
  • lyanesselyanesse Member Posts: 1
    I'm having the same problems with my 2011 Prius, purchased in July 2011. After only a month or so of driving it, I started to become scared daily by the unsafe driving conditions due to the car's tendency to lurch forward while braking over bumpy ground coming to a stop. It does not help to always "brake early and hard" as another poster suggested because the car simply fails to brake when it hits potholes - it doesn't matter how hard you're pressing the brakes. I also brought this to the dealer's attention last fall and they said they checked the brake system and there was "nothing wrong, that's just how the braking system works." I know that this exact issue is a problem on 2010's but have not found a recall for 2011's and the dealer claims there is no issue on my car.

    Well, now this "non-issue" has caused an accident as my husband was driving my car last weekend and the car lurched forward while he was braking over potholes (there are a lot of them around San Diego) coming up to a stoplight and it didn't stop and it resulted in him rear-ending someone. There was no damage to the Prius, just some dings in the bumper of the other car, but $2000 later I feel pretty upset that my Prius clearly is not reliably safe to drive. I'm going back to Toyota soon with my documentation in hand that I brought this issue to their attention months ago and I'd like to see what they have to say now it's led to an accident because they ignored the problem.

    I also have other electronic issues with it - smart key system not working well either. It completely failed about 2 months after I got it, then Toyota reset it and it hasn't worked as well as new since. Oh and the radio system sounds terrible, with lots of electronic interference that makes the sound very muted. It will sound clear for a split second when I turn the car on or switch from CD to radio, and then it gets muffled. Dealer also found "nothing wrong" on the radio. I do like the car but am seriously frustrated to have spent so much money on a car that does not perform as a new car should or provide the level of safety a consumer would expect.
  • jacquescjacquesc Member Posts: 13
    Keep up the pressure on these problems. I have tried a ton to really fight these issues we are all having. However, on this forum every response seems to be from someone that has been employed by Toyota to pacify the complaints.
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