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Sudden Acceleration - It Happened To Us Today

Discussion in 'Gen 2 Prius Main Forum' started by chrysotile, May 6, 2010.

  1. cycledrum

    cycledrum PSOCSOASP

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    Ever heard of trail braking in sport motorcycle riding? It's braking, sometimes deep into corners.

    Can use braking whenever needed, no matter where, straight, in a turn, etc.. the key is to do it right. Have to be easy with brakes, not jab them.

    Something ya learn with backroads riding.

    B26.jpg

    Yeah, I'm the albatross on the little Red bike. Good times.

    IMG_0040%20%28Medium%29.jpg

    Guy standing behind me outruns everyone on this Ninja 250. 20yrs. racing helps.

    But at pace I drive the Prius, I brake just a bit before corners.

    ooops back to topic :D
     
  2. dan2l

    dan2l 2014 Prius v wagon

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    Hello Chrysotile,
    Sorry for some of the insensitive posts. I do fully believe this. I also have done much research into the San Diego incident and after ready the police report I believe that the Prius did accelerate in that incident.

    I do feel fully safe in both of my Prius's. Also I feel that I have a good explanation of what may be happening.

    In a post on the Yahoo Prius site a person did have this problem several times and it all went away when he replaced the 12v battery.

    Have you had any problems with the car not going "ready" because of a low 12v battery? Before this drive did the car have anything that may have caused or allowed the 12v battery to be a little low?

    What happened in the case of the battery is that as the car is booting up the many computers, they do not sync into each other properly. The car may "go ready" and run just fine until an communication between the computers is not understood correctly and then one of the computers takes an action that is not correct.

    In your case the hard turn triggers the computers to communicate something that they had not done since the car booted up. This is the trigger for the event. But the real problem is the boot up did not happen correctly.

    Thanks,
    Dan
     
  3. Politburo

    Politburo Active Member

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    As I understand, most of us only got the notice this week. Someone who works in a service department got info about it 3 weeks ago. Are you sure your pedal was modified?
     
  4. chrysotile

    chrysotile New Member

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    Hi Everyone. Thanks for the feedback, input and ideas and thanks for (the majority) taking this seriously. We are not trolls. As I said, we love our Prius and have been very happy with it (except for the annoying tail light problem) so we have no axe to grind here with Toyota.

    First a clarification - my wife was not going through the intersection when it was a red light, I asked her again and she said the light was green. And yes, she did "brake through" the intersection (you need to know how safe my wife drives - very safe). The point I was trying to make was that she had her foot on the brake when this happened and she was executing a right hand turn.

    The pavement was dry and clean and there was no extraordinary road bump, pothole, construction work, etc. in the location of the road where this happened. Having said that, we do live in Pennsylvania - which should tell you all you need to know about the general condition of the road (or for that matter - any road here in PA). All Pennsylvanians will know that of which I speak.

    Is it possible she hit a bump in the road while making the turn and braking? Yes, as a matter of fact, given the terrible condition of PA roads, it is surprising she could find any road where she was not constantly driving over bumps, or worse.

    And that is the point - she has driven this Prius, for almost three years, through this exact same intersection and roadway - hundreds and hundreds of times before and she never experienced anything like what happened.

    Some specific questions were asked I will try to answer as best I can:

    Never any problem with the Prius not going "ready" or a low voltage battery. We have had zero issues with the starter or battery since we owned the car.

    How many miles on the odometer? – 26,000 (roughly)

    Are the tires original equipment? – No brand new (only a few months old and the tread is fine. Not sure of the make, I’ll look later and post.


    How much tread depth remains on the front tires? – Excellent tread depth, tires are only a few months old.
    Did she also hear the engine rev loudly? Yes she did hear the engine rev up.
    Are you saying you and the wife are driving with no floor mat on the driver's side? – No, we have replacement (not standard issue that came with the car) rubber mats. All rubber, no cloth.

    How long did it happen? Just long enough for her to react, hit the brake harder, and for the traction light to come on. I am guessing 1-2 seconds, maybe 3 seconds max.

    Was there any pothole on the turn where she was braking? No (see my comments above about PA roads).

    Any manhole cover there? No.

    Our experience today at the local Toyota dealership was very good. We were very satisfied with how seriously they took our report. They did not try to brush it under the rug or insinuate that my wife did something wrong (i.e., foot on the brake and accelerator at the same time), or that we had ulterior motives (i.e., media attention, lawsuit, etc.). This reaction was very different than the ones we received yesterday (the day the incident happened) with the service managers who were both very dismissive.
    We met with the dealership general manager and assistant manager. They were both very kind and helpful. Together, we completed the survey that Toyota must complete for any report of a problem (part of the agreement Toyota has with the US as part of the recall). We gave them the same information that I have posted here, and more. They assured us the form will go to Toyota and the NHTSA. I have no reason to believe otherwise.
    They then conducted a full inspection and check of the vehicle using their best mechanic. He thoroughly checked all systems and diagnostics and found nothing wrong – they felt the car was in good working order.
    Still – though the vehicle checked out well, they were a bit concerned about how this sudden acceleration happened (while braking) and this was apparently unusual enough that they are bringing in a Toyota tech specialist from California to look at the car next week. So we left the Prius with them until this tech specialist has a chance to examine it. They gave us a very nice Corolla as a free rental to hold us over until then.
    I hope they can discover something through this inspection process because what happened does sound strangely similar to some of the reports we have read in the media about sudden acceleration.
    Regardless, I don’t know if my wife will feel comfortable in the Prius again. Not that she will feel the car is “unsafeâ€. Just, that comfort factor may be gone for good. We’ll wait and see.
    I’ll keep everyone here posted as this moves along.

    Thanks again to those of you who were nice enough to offer advice, ask questions, etc., in an open minded and nice way. We do appreciate it.

    Pat and Ann
    Bouncing down the roads of Pennsylvania
     
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  5. robbyr2

    robbyr2 New Member

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    I have an 01 Chevy Blazer with ABS that I have taken on some pretty rugged 4WD roads over the years. The loss of traction which occurs when the tire loses contact with the ground leads to a scary feeling. It can happen on a rough road or with just a little bit of sand on the road. I've driven on ice and hydroplaned a couple of times and it is scary. The feeling is amplified with the Prius (not that it goes off road but Colorado roads are not getting any better) as discussed by others.

    The "nice" part of this scenario is that gravity is going to reconnect tire to ground and you will regain control. If the pavement is dry and clear, keep braking. Even if your Prius has developed a mind of its own, the brakes should keep you from going too far. I know that is opposite what you do on ice or snow.

    Even better is that Toyota is working on it. Even the service guys you talked to the phone are just human... you might have caught them right after a really nasty customer, or just before their lunch break, or well, you know.
     
  6. The Electric Me

    The Electric Me Go Speed Go!

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    That's an interesting theory. I find it "funny" that is basicly what Steve Wozniak said, just re-boot the automobile. That's an interesting enough theory that Toyota should investigate it. If true they need to boost the 12v power, change the guidelines for maintenance and/or provide a warning system if the 12v should fall into a range that would allow this anomaly to occur.

    It's an interesting theory, but at this point it's just a theory.
     
  7. uart

    uart Senior Member

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    Ok that's very interesting. The reason I asked is because most people seemed to think that it was just the momentary reduction in braking effort that you can get when the car switches from regenerative braking to ABS friction braking (when the road is suddenly bumpy or slippery). However I didn't think that could cause anything as dramtic as what you described and I think the engine revving proves that it was real acceleration and not just a reduction in braking effort. Very strange, I hope they can figure out what caused it.
     
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  8. 200Volts

    200Volts Member

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    Try this braking experiment to duplicate the "issue".
    Find some ROUGH railroad tracks that cross a road.
    Approach the tracks at a moderate speed.
    Way before the tracks, apply a steady light-moderate brake pedal force, EVENLY.
    Try to cross the tracks about 15-25 mph, do not alter the brake pedal pressure.
    Feel what happens when you cross the tracks!
    It "feels" like acceleration, because you are not DE cellerating as fast.
     
  9. LoveMyPriusIII

    LoveMyPriusIII New Member

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    If the engine was warmed up wouldn't the engine have been off approaching and braking into the turn? In either case she heard the engine rev up during the acceleration surge which cancels out the braking theories.
     
  10. JimN

    JimN Let the games begin!

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    Pat & Ann, what is your tp (tire pressure)? I suspect it is very low if you chewed through a set of tires in 26000 miles. While you are looking at your new tires read the max sidewall pressure then inflate the tires to that number. A coworker replaced the Integrities on his 2007 at 70000 miles & he still had some tread left.

    If the intersection is close to the dealership take one of the guys through it. The 2nd easiest way to piss me off in the Service Dept is to tell me "can't replicate the problem".

    As long as they have the car, ask the dealer for the 3 voltage readings in writing for the 12v. If there is some problem with this show them how to get into Maintenance Mode & get 2 of them. For the 3rd you'll need a gauge plugged in the OBDC port under the steering wheel.

    Something is wrong since you are burning out a light. Get the problem fixed while the car is under warranty. After 3 years/36000 miles & 1 year on the replacement part you'll be paying for the light.

    Your description of the car has not helped your credibility and is the hallmark of a troll.

    I wouldn't trust the dealer or Toyota to report your situation to anyone. File your own complaint at: Office of Defects Investigation (ODI), File A Safety Complaint

    Take the AAA driving course to improve your DMV record & get an insurance discount.

    Best wishes for getting a satisfactory answer & your electrical problem fixed.
     
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  11. happyman

    happyman New Member

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    i agree
     
  12. bisco

    bisco cookie crumbler

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    my sister in law has an accord, my brother in law has a camry. one time, after all the u/a stuff started, she had to use his car. when she got home, she told him that it took off on her suddenly for a few seconds. he rolled his eyes when he told me, he has put 80,000 miles on it without incident.:rolleyes:
     
  13. chrysotile

    chrysotile New Member

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    Thank you for the analysis. She is sure she heard the engine rev up when it happened. I hope they can figure this out too.
     
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  14. chrysotile

    chrysotile New Member

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    There was nothing wrong with the original tires. They still had good tread. We got the new all season tires when it started snowing (and kept on snowing and snowing) here this winter.

    The tire pressure on the tires right now is fine.

    We know something is wrong because the lights keep burning out. As we have had the car back to the dealer to repair/replace the tail light problem at least four times, we assume they must have tested your theory and checked the voltage. They have had ample opportunity to do so.

    The intersection is not close to the dealer but we offered to meet this tech rep who is coming in from California at the intersection if they want to see the road and try to simulate what happened with our Prius. We will gladly do what ever it takes to help them get to the bottom of this.

    Thanks for the advice and help.
     
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  15. robbyr2

    robbyr2 New Member

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    ...keeping in mind that Mr. Wozniak has told the world that his complaint was entirely a hoax...
     
  16. uart

    uart Senior Member

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    Yes influence of the news hysteria over the whole u/a thing cant be ignored here. It's made people way more inclined to jump to conclusions of "computer/electronics glitch" instead of more mundane explanations like pressing the brake but having the side of the shoe contact the accelerator as well for example.
     
  17. ETP

    ETP 2021 Prime(Limit),24 Venza Limit,B52-D,G,F,H

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    Very bad to drive with both feet! You will not pass your drivers test in most states.:D
     
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  18. BAllanJ

    BAllanJ Active Member

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    Except if you have a manual transmission, I suppose.
     
  19. auricchio

    auricchio Member

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    That's actually not a bad thing. Just like defensive driving, something like this keeps us on our toes. Having this "edge" prepares us for any event, whether caused by the car, other drivers, or road conditions.

    As for the engine revving, it's very possible to mash both pedals when slamming the brake hard. So the revving could be the result of sudden, hard application of the brake in a panic situation---and not something that preceded the event.

    The road condition may be different than you think because we've just come out of winter. Even a handful of loose gravel on the road can cause enough of a skid to trigger the traction control and affect braking.
     
  20. CharlesJ

    CharlesJ Member

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    I would also recommend you report it to the Federal government agency concerned with car safety, Home | National Highway Traffic Safety Administration (NHTSA) and file an on line report.
     
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