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Toyota Prius Brake Problems



  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAPosts: 7,961
    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.

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  • wwestwwest 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 Pennsylvania Furnace, PAPosts: 7,961
    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 ;)

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  • john1701ajohn1701a 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 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 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 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 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 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 Posts: 205
    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 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.
  • 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.
  • 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!
  • 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 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 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 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.
  • 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 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.
  • 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.
  • 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 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 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.
  • 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.
  • 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
  • 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.
  • 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 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 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:
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