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Toyota Prius Brake Problems



  • Hi,

    The ZVW30 Prius, 2010-current, has the redesigned brake system and the recent recall to get rid of a rare, brake pause. The NHW20, 2004-09, has not been recalled but there are reports that it has a similar but less severe pause. The NHW11, 2001-03, is my commuting car and none of my tests have replicated the brake pause.

    2010-current Prius - SSC-A0B

    You don't have to wait on a letter or call from the dealer. Call your local Toyota Service Center and schedule an appointment. If the service writer gives you any grief, ask to speak to their manager ... keep going until you get the right answer, "Yes, come in and we'll fix it." Alternatively, call another Toyota dealer or ask them if you should call the local newspaper.

    The problem is rare and intermittent. Probably the surprise, more than anything else, catches folks off guard. Just press harder on the brake and the car stops almost instantly. In the meanwhile, keep your following distance on the long.

    2004-09 Prius

    There are reports but sad to say, I'm not having much luck documenting the pause. I have an accelerometer that clearly showed the ZVW30 brake pause but I've yet to find someone with a NHW20 to test. I may have to rent one.

    We have a poll going on in PriusChat about the brakes and the numbers are:

    55 - Yes, I want it fixed (22%)
    41 - Yes, However it doesn't bother me (16%)
    153 - No, I don't feel my GEN II Prius has a problem (61%)

    So over half don't see a problem. Only 22%, 1 in 4, wants a fix.

    2001-03 Prius

    I have one and following the same protocol as our ZVW30, I can't find any pause in the braking using the accelerometer.

    Bob Wilson
  • sthogesthoge Posts: 28

    Perhaps you could post your general area and someone that lives near you could volunteer.

    I have a 08 Prius and I have experienced the the momentary release of the brakes when hitting a pothole or rough road, but immediately after the brakes grab. I have even hit areas of ice and the ABS has always kicked and assisted in a timely stop. So over all I am more than happy with the performance of the braking system. Although I wouldn't complain if they removed or shortened the momentary release when you hit a pothole.
  • jacquescjacquesc Posts: 13
    I'm not saying you are not being truthful - however, I am saying you must have not take all situations into consideration. If you were behind someone at a safe distance and they slammed on the brakes for whatever reason. Then, you attempt an emergency stop and a bump in the road causes a couple seconds of complete loss of braking... almost guaranteed an accident will occur. The next step (after making sure that everyone is ok) is deciding who's then who is at fault?

    I stand by my prior accusations that the poor engineering of the car is the reason for the accident. Thus, Toyota is at fault for not addressing the problem in the 2nd & 3rd generation Prius.
  • You wrote:

    "Perhaps you could post your general area and someone that lives near you could volunteer."

    I'm in Huntsville AL and had one possible volunteer but he never followed up. So I'm thinking rental car. But I'll need a rainy day for the test.

    The other option is the iPhone and iPod Touch have a built-in accelerator chip. I have no fiscal interest in them but there are at least two applications that record accelerations fast enough to gather engineering data over short intervals. Dynolicious Logger is one I've tested and within short intervals, 30-45 seconds, the data is usable. Unfortunately, I'm see long term drift that limits it to mostly short tests like the brake pause.

    Bob Wilson
  • whitecliffwhitecliff Posts: 2
    edited March 2010
    Well it happened again yesterday. Fourth time on my new (January '10) Prius.
    I was slowing for a turn, going about 18mph and the car surged ahead.
    I thought there was a recall but I still haven't heard anything from them yet.
    Does anyone know if the "flash" worked?
  • If your car was made in the last week of January, it already has the post-recall brake configuration; your dealer will know. Mine, bought Decemer 12 needed the fix and I got it February 15 in a one-hour visit to the dealer. I still have not received paperwork from Toyota Motor Sales USA about the recall, but I did get an email about it from the dealer about a month ago and I immediately made an appointment. The problem it fixes, disconnection of the ABS momentarily when you hit a bump or one or both traction wheels lose road contact, is something I experienced early and got used to. I did not really need the recall because I knew my brake was always operative and I use it automatically in those situations, with no need for ABS support. A couple of times the ABS activated on snow, and I did not like it all, and it did not help (I did not expect it to).
    On the "other" brake issue, my dealer told me in a phone call yesterday that all Toyota hybrids " already have brake override." I think that is not the correct use of the term, because what the service department told me was that the brake pedal always "has precedence" if both accelerator and brake are pushed simultaneously. I think true brake override would mean the engine shifts to neutral when both pedals are pushed, with no need to touch the shift. The dealer is mailing me a 16-page hardcopy explanation of how the Prius brakes work; she said it was technical, but I am very interested in reading it. As far as I know, it is not available on the Web, but your dealer might have it.
  • Your engineering and Prius knowledge is breathtaking. I am no engineer, but I have learned a lot from your posts. Thanks for locking onto this set of issues and letting us learn what you are finding and what the loose ends are. You are helping me retain confidence in my 2010, the quirks of which I have mostly found--I think--and adjusted to. I remain impressed with the car and hope Toyota can manage its way through the current mess with honesty and sincerity. There is a lot of bad information and also disinformation (I sense) floating around.
  • Hi Everyone,
    I had posted a while back about my accident in Dec 2009 that I had with my 2009 Prius, where my brakes failed at a low speed and rear-ended the car in front of me. I've been seeing lately a lot of people noting that 2nd gens have been also experiencing the problems and are upset that Toyota hasn't done anything to find a solution. I am one that is very upset as well. I have brought the car in to be inspected and called Toyota multiple times about my brakes before and AFTER the accident and they keep telling me "there's nothing wrong w/ them" despite almost everyday occurences of going over potholes and feeling that temporary loss of sensation from braking. My favorite was when they were trying to argue with me on the phone what happened- "your car must have slid on something, like ice." <---- Really? I did a walk around my car after the accident.. there was no ice/ no snow/zilch. Your car has a defect!! Oh and my other favorite Toyota rep. telling me to just trade the car in if that's how I felt. Overall, I'm frustrated and don't know what's the next step about this car and how to deal with Toyota...

    So here's my question: Any one aware of any civil action suits involving the 2nd generation brakes? Because I would love to know so I can hop on board and have Toyota solve the problem for the whole Prius line and feel safe driving it again. I've absolutely had it with Toyota right now.
  • whitey9whitey9 Posts: 138
    So why are you still driving it?
  • wwestwwest Posts: 10,706
    "..I was slowing for a turn..." " surged forward.."

    In the circumstance you describe the VSC may have activated as the result of detecting some minor level of understearing/plowing, or possibly even a bit of over-stearing. If you are already on the brakes then VSC activation will sometimes result in "unbraking"(***) one of both front wheels.

    *** Sometimes that might mean an instant disabling of regen braking and the resulting "lurch" forward "seat of the pants" feeling. If the frictional brakes are also already in use then the regen will be disabled along with unbraking of the frictional brakes on one of the front wheels.
  • cgollihercgolliher Posts: 16
    edited March 2010
    Last night I was out driving on a rural road, came to a hair pin cure, one I have driven through hundreds of times, couldn't seem to slow down enough to make the curve and went straight into the grass embankment. Car is not at the auto body shop with I am sure at least $5,000 or more damage to the front end. I have only had the car for three weeks. After it was all over, I just could not understand what or how this happened. After having some time to replay everything in my mind, I believe it is the prius brake issue. Country road, potholes, and some gravel on the road. Wow, my honda accord never had a problem with this cure which I travel almost daily. I am very concerned and upset. I was only going about 30-35 mph when I began breaking. Any one else exp this type of problem?
  • 07prius07prius Posts: 10
    I believe that I have (see earlier posts) but I do not have enough hard data to know for sure, ie: I do not know the exact distance I was away from the car I rear-ended, although my habit is to travel at least 100 feet behind cars in front of me, as I know that tail-gaiting is unsafe. I, too, was only travelling 35-40 mph, if that, as I remember I had just come around a turn at about 25 mph (the speed limit for that turn, even though most people were driving faster than that). I often use cruise control to improve my gas mileage and prevent myself from speeding, and I was just getting up to speed as the speed limit after the turn was something like 40 mph. Anyways, like I said, the are too many subjective factors in my case. I have a 2007 Prius.
  • 07prius07prius Posts: 10
    P.S.: For me, I think the problem is more to do with the TRAC system than the brakes. I took my Prius to the dealer and reported this to them, however, go the same line as everyone else: "The car's operating as it was designed to." TRAC cuts power to the engine and brakes when the computer senses that there's even a slight loss of traction, which naturally happens when panic braking, and this is not what needs to happen when in a situation where panic breaking is necessary. Yes, I know we're all better drivers than everyone else, but sometimes there are situations where panic breaking is necessary no matter how safe of a driver you are.
  • I had my 2010 Brake Fix about 3 weeks ago.(after reporting the problem to the dealer and being told there is nothing wrong 4 times) The problem of slowing down, hitting a bumb and the temporary loss of brakes is gone. What the fix has now created is another problem that I have now experienced 3 times since the "fix"- when I am slowing down the car and hit a pot hole or bumb while turinng the car lunges forward. It is not something that I can not control, but the car litterally rattles and moves forward. I have contacted toyoto corporate and have an appointment with service for Friday- I can pretty much guarantee they will tell me as they have in the past there is nothing wrong with the brakes- my experience with my Prius has changed my opinion of Toyota, and I truly believe the Prius is over "electronic" and they simply do not know how to fix it- My original intention with the 2010 was to allow my 16 year old twins to drive this car when they are able to drive. I would never permit a new driver to use this car- the braking is still a major issue and Toyota after the recall has failed to address the "new" problem..shame on Toyota
    I have every intention of seeing this through, I did not buy a new car only to have to alter my driving, while Toyota denies their Gremlins...I intend to utlilize my rights under the Lemon Law in my state and through arbritation..the question is, when they refund my money what "car" shall I buy? S
  • cgollihercgolliher Posts: 16
    I also purchased my new prius with all intentions of allowing my 15 year old drive this car as he learns to dirve. NO WAY will I allow him behind the wheel of this Pruis!!!!! It could be his coffin!!!!!!!!!!!!! If your car is lunging forward after exp uneven roadway, that is what mine did after the brakes failed. I do not believe that Toyota totally understands how to completely fix all their problems. I DO NOT TRUST TOYOTA at this time !In response to your question as to what to purchase next, check out the Ford Fusion hybrid. It is a nice car with good gas mileage and no reported problems as of this date. As for me, after my collision, and the "NO RESPONSE" I am getting from Toyota, I am going back to a car made by an American car company. I had 3 Ford Explorers during their recalls. Ford was prompt and I felt taken care of, and most of all safe.
  • hal_cathal_cat Posts: 11
    The media and many posts on this board comment on how the problem with the Prius and other Toyota cars could be electronic. I think we need to be more accurate. I don't believe the electronics (circuitry) is the problem, and when Toyota says the electronics isn't the problem, I tend to believe them.

    My strong belief (based on years of designing software for engine and transmission controllers) is that the SOFTWARE is the problem. Either in the ABS or the Engine controller, or quite possibly the communications between them. The low incident rate for failure is a primary indicator to me tha the problem is software rather than hardware - hydraulic or electronic - since the physical problems would tend to persist continually rather than rarely.

    Note that the 2010 Prius recall involves "flashing" the ECM (reprogramming the Engine Control Module).
  • whitey9whitey9 Posts: 138
    edited March 2010
    Did anyone see the report that was featured all day long on all the news channels yesterday ( Tuesday, 09 March 2010 ). It featured an older man and his '08 blue Prius ( license # FRUGL 08 ). He was reported to have reached speeds of 94mph and was "rescued" by a state trooper.
    The ordeal lasted some 30mi as he swerved in/out of traffic to avoid collisions.
    The thing that surprised me was the fact that the man was afraid to place the transmission in "neutral", since he did not "have a lot of experience with these transmissions", and that he was afraid the car would "flip" if he shifted into neutral. I don't understand.
  • wwestwwest Posts: 10,706
    Maybe the driver knew more about the Prius, or any HSD, CVT, PSD, Power Split Device, than the average driver. These HSD systems do NOT have a TRADITIONAL neutral gear "position". The ICE and the two electric motors/generators are ALWAYS mechanically coupled to the drive wheels.

    IMMHO it is entirely possible that the driver tried shifting into neutral earlier but with no effect. Remember that if this is a cruise control problem the CC disables itself below about 35MPH. As is apparently what happened with Ms Smith's incident.

    If the brakes did not work to put the HSD system into regen mode then something OTHER than a stuck gas pedal was amiss. The CHP officer stated that he saw the brakes lights going on and off so we know the brake light switch was working. Even if the driver was at fault and for some reason kept the gas pedal fully depressed the brake application should ALWAYS result in the HSD system switching into regen mode.

    That latter effect is exactly why Toyota/etc has been saying the HSD vehicles already have a BTO, Brake/Throttle Override. Apparently they do not.

    Had that incident happened to me I might have tried "shifting" into neutral but would have (hopefully) been prepared to quickly shift out of neutral in case the result was totally LOCKED front wheels.
  • chucko3chucko3 Posts: 793
    edited March 2010

    Not necessary. With a low rate failure like that I would think it's a hardware issue.
    The software is the same for every model. So if it's the software issue, the problem should occur in every car same model. Unlike hardware, software does not break down over time. There are so many things which can cause hardware intermittent glitches: power surge, temperature, bad components, loose soldering, etc.

    If the hardware glitch or the problem can be fixed or prevented by the software, the fix will be done by the software because it's easy to replace and cheaper. Been there done that.
  • To shift to N or not shift to N is argued both ways by a variety of different people, some of them apparent experts on this forum, and I remain confused. BTW, I drive my 2010 confidently and am not really worried about UA, but the constant din of hyper-amplified reports and complaints make me want to be prepared.

    Even at a standing stop, the shifter/joystick seems almost completely fluid, and getting it to stay in neutral takes a tiny bit of concentration, as there is no reassuring click, the way a mechanical shift would work. Reverse and drive are easier because they are at the ends of the pattern and thunk lightly into place.

    I have tried shifting to N at low speed, and have some concern about inadvertently putting it into reverse while I am moving.

    I am really concerned about the possibility that at, say, 50 or 60mph, the wheels might lock, as you suggest in your comments.

    What is, or where can I get, the definitive advice on shifting to N? Do it/not do it at what speed(s)?

    This is one area where Toyota is truly irresponsible, as it does not deal with this issue in a straightforward way, nor the companion issue of whether or not to try to kill the engine with the power button.

    I have talked with my dealer, read the Toyota web site, read a tech manual that dealers use, read Toyota pronouncements in the media, and the advice is still not fully clear or consistent. (And, amazingly, neither is the presence or absence of real or functionally equivalent BTO on specific cars. It iis as if the Toyota PR experts are singlehandedly creating a reason to commit seppaku.)

    Toyota is hedging simple solutions for some reason, perhaps because it still wants to attribute all problems to Toyota's maldesign of the floor mat (in my view a ridiculous red herring in any Prius), sticky pedals (on cars other than Prius) or driver error. My personal guess is that most UA incidents are actually due to driver error. But, in a disconcerting pattern, Toyota has not convincingly shut the door on the possibility of a software glitch or some induced RF interference with the ECM.

    I did not think it possible a month ago, but Toyota is well down the road to killing its brand. Half the problem is the idiotic media, self-serving experts, and clowns in Congress and DOT. However, Toyota is proving to be an incompetent crisis manager and awful handler of customers.
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