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Prius Surged Forward - Really

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by kfetty, Mar 24, 2009.

  1. kfetty

    kfetty New Member

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    Hello,

    I've been a member since my purchase of a 2006 Prius in 6/06. I love my Prius. It has 12,000 miles in almost 3 years -- I live on Long Island and take the LIRR to work every day. It's the greatest car in the world. Period. I've bought the hoodie, sun visor and side mouldings along with the great rubber mats that are so much better than the originals, although I still have the originals.

    Anyways, last Friday 3/20/09, the Surge Forward happened to me. I am not a troll and I hope I won't be met with suspicion or doubt.
    I am simply worried and hoping to get some decent advice from this group as you are the experts on the Prius. There are 2 different threads on this subject in 2008 "Prius Surged Forward".

    I was at a light stopped dead. Not in neutral. I accelerated when the light turned green. The car shot off like a bullet. Much faster than I would ever take off. I was approaching a small town bridge and although I was scared, I kept my cool and rode the brake to slow the car down. Very quickly after the bridge, I pulled over safely into a parking lot and turned off the car. Started again and no problem. Nor have I had one since. I did research and found one article on the consumeraffairs.com website with similar stories, although some of those ended with accidents. I was lucky.

    I called Huntington Toyota (great dealership) and although I didn't speak to a mechanic, I spoke to someone who said bring it in and we'll check it out.

    Now the article I found on consumeraffairs.com (google -- Toyota recalls floor mats) says that the mats were recalled (I vaguely remember reading about this in the press at the time in 2007 but thought nothing of it at the time) but people aren't convinced it was the mat or driver error. As I say above, my mats are the rubber, all weather kind. Nothing was remotely near the gas pedal.

    The real fear I have is that this could happen anywhere anytime - in a shopping center, near a school whatever. I will be vigilant, but one never knows -- it only takes a second.

    This is the first and only issue I've ever had with my Prius. The article I mention above says that an engineer (not a Toyota engineer) thinks it may be related to cruise control. I have never used cruise control in my life, on the Prius or otherwise. That makes sense to me as the 3 minutes or so that I was zooming forward and riding the brakes it felt like the car was maintaining a fast speed.

    Anyways, I'm seeking advice here and hopefully someone will have ideas.

    1) should I bother with Toyota who will inspect everything and tell me everything is ok? There is also a Toyota Customer Experience Center toll free # to document issues like this and sometimes a recall results if enough people experience a similar issue.
    2) is it possible to have Toyota disable cruise control only? I never use it and it would make me feel safer
    3) any other thoughts or ideas?

    Thank you in advance for any ideas or opinions and please realize that I am not bad mouthing my Prius or Toyota or Prius' in general. I simply don't want to experience that runaway acceleration again. It was unnerving.

    Karen
     
    #1 kfetty, Mar 24, 2009
  2. ceric

    ceric New Member

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    The first thing I would guess is the gas pedal. Many modern gas pedals are not mechanical, but driven-by-wire. If there is anything wrong with the position sensors (stuck, for example, temporarily), you could experience a surge in speed.
    It could also be the mat. But if you say NO, I will believe you.
     
    #2 ceric, Mar 24, 2009
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Karen,

    Very sorry to hear about your experience. In principle, the braking available from the braking system should exceed the power that the drivetrain can produce. Did you depress the brake pedal as hard as you could - or were you too startled to do so?

    - Is the driver's side rubber mat secured to the floor with the two plastic pins?
    - Any debris on the floor?

    If you can't find any obvious reason for the accelerator pedal to be stuck in place, I suggest you have your dealer check out the car (although they may well tell you that no trouble was found.)

    Cruise control is a feature of the hybrid vehicle ECU, so it can't be disabled in any meaningful way. Base model Prius do not have cruise control, which means that the cruise control switch on the steering column, the double-pole brake light switch, and the associated wiring harness is missing. However the HV ECU still contains the circuitry for this function.
     
    #3 Patrick Wong, Mar 25, 2009
  4. RWB

    RWB New Member

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    Even if enabled, the Prius Cruise Control is not active under the speed of about 40 km/h. Each time the speed drops below that, the cruise control switches itself off and forgets its former settings, so the driver has to set and resume the cruise control each time when he exceeds that speed again. Therefore I think that the chance that the surge is related to the cruise control is nil.
    I've experienced such a surge once myself - yes, it's scary - but hitting the brakes immediately stopped it and I positively found out that the rubber mat caused it. It never happened again.
    B)
     
    #4 RWB, Mar 25, 2009
  5. jayman

    jayman Senior Member

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    Really? No, not *really*

    With my Prius at highway speeds, I floored the gas with my right foot and then stomped the brake with my left foot. Car quickly stops

    With my FJ at highway speeds, same test as above with same result

    Although it's entirely possible that a handful of *any* car series made can experience unintended acceleration *combined* with brake failure, this is nothing new or unique to a Prius

    Please don't mention Consumer Affairs. They're a bunch of ambulance chasing lawyers. If you believed them, every consumer item on the planet was evil and out to get you
     
    #5 jayman, Mar 25, 2009
  6. qbee42

    qbee42 My other car is a boat

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    Ditto on Consumer Affairs. They specialize in making mountains from molehills.

    This has been covered in the previous threads, but needs to be emphasized:

    1) The throttle system on the Prius is drive by wire, which means there is no cruise control system. Cruise control is simply a setting on the drive by wire system.

    2) There have been some problems with floor mats. These were caused by the wrong mats, or not hooking the mats to the two hooks on the floor.

    3) The brake pedal will always win if you use it firmly. If the car starts accelerating again, do exactly what you did before: stomp on the brake and stop it.

    4) It is possible to have a problem with the sender on the accelerator pedal. It's a dual set of hall effect sensors, so they are very unlikely to fail, but it's not impossible.

    Tom
     
    #6 qbee42, Mar 25, 2009
  7. richard schumacher

    richard schumacher shortbus driver

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    Do your mats engage with the hooks? If not then they can ride up.

    Do you drive with two feet, or one foot?

    How old are you? (Sorry about that, but reports of this phenomenon appear to be strongly correlated with the driver's age.)

    After the car is powered ON and OFF more than a few times most or all of the problem codes will be cleared and the dealer may be unable to diagnose a mechanical problem.
     
    #7 richard schumacher, Mar 25, 2009
  8. jayman

    jayman Senior Member

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    Usually, when the drive-by-wire pedal goes Tango Uniform, there is no acceleration at all. Semi trucks made in the past 10 years frequently have drive-by-wire throttle input, and if a driver has a habit of getting in with muddy, slushy, salty boots on, all that stuff can corrode the sensor in the pedal assembly.

    Eg a Detroit Diesel 60 series with DDEC IV electronic fuel injection. It will refuse to go above idle and will throw a code. If the crankshaft sensor goes Tango Uniform, the motor will then quit and refuse to start, and will also throw a code

    One thing Prius drivers should keep in mind is that the car has a primative black box. Say there is an "unintended" acceleration into a brick wall, a gas station, or another car. When the airbags pop, it will freeze frame such items as speed at time of impact, seat belt use, and whether the gas or brake pedal is applied
     
    #8 jayman, Mar 25, 2009
  9. kfetty

    kfetty New Member

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    I'm 59 years old. I drive with one foot. The rubber mats don't seem to engage with the hooks, but in the daylight tomorrow I will throughly investigate. Understood about the problem codes perhaps being cleared.
    Thanks,
    Karen
     
    #9 kfetty, Mar 25, 2009
  10. kfetty

    kfetty New Member

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    I didn't slam my foot on the brake as I assumed the car behind me (this is Long Island!) would crash into me if I stopped dead. However, if you are saying that by hitting the brakes hard, it knocks the car back into normal behavior but doesn't stop the car dead, then I will try this one out. I'll go to a deserted area and test this tomorrow. I understand that the issue is not with the Prius but can be any car and thanks for the tip about consumeraffairs.com.
    Thanks,
    Karen
     
    #10 kfetty, Mar 25, 2009
  11. kfetty

    kfetty New Member

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    Thanks so much for the comments about the cruise control. I'll stop thinking about that. Interesting that you experienced a surge yourself -- and I will hit the brakes (instead of slowing and riding the brakes). I will definitely remove and thoroughly inspect the mats to make sure they are not a problem.
    Thanks,
    Karen
     
    #11 kfetty, Mar 25, 2009
  12. kfetty

    kfetty New Member

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    I wasn't really startled and on one level, I felt entirely in control. But it was scary as I was afraid perhaps the car wouldn't turn off or something, but once I pulled over and could safely stop it was fine. As I said, I simply rode the break -- it wasn't for long. As I was entering a bridge I didn't want to stop on the bridge and cause a problem, so I exited as soon as I was off the bridge.

    There's no debris -- I keep the car neat as a pin, but will check out the mats very closely tomorrow. I will go to the dealer tomorrow and have them check out the pedal just to make 100% sure and I feel better about the cruise control and understand now that it's not the issue. I got the Package #5 including the GPS system but not the DVD player so I don't think it's the base model. However, I don't use the cruise control - so no issue there. Long Island is stop and go where I live, which are perfect driving conditions for the Prius as we all know!.

    Thanks again,
    Karen
     
    #12 kfetty, Mar 25, 2009
  13. kfetty

    kfetty New Member

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    At the dealer tomorrow I will check out the car and especially the pedal. The mats I'll check out before I go, but I'm sure they will too.

    Thanks again,
    Karen
     
    #13 kfetty, Mar 25, 2009
  14. richard schumacher

    richard schumacher shortbus driver

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    Good luck! Please let us know what you find.
     
    #14 richard schumacher, Mar 26, 2009
  15. EZW1

    EZW1 Active Member

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    If Toyota engineers are worth a grain of salt, and I'm sure they're worth much more, then they would've designed the drive by wire system to default "dead" if there's a component failure. That is, if the crank sensor, or pedal sensor, or any other safety-related sensor should fail, the car should stop - at least the engine and inverter should shut down.

    Now, if your car took off on a very high acceleration, there had to be some type of outside factor that caused it such as floor mat, mechanical sticking joint, radio interference, etc.
     
    #15 EZW1, Mar 26, 2009
  16. Frayadjacent

    Frayadjacent Resident Conservative

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    I think I experienced this type of thing in another vehicle that had drive-by-wire throttle. It was in fact the floor mat. In that car, there were no hooks to keep it from sliding forward.
     
    #16 Frayadjacent, Mar 26, 2009
  17. kfetty

    kfetty New Member

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    Hi Everyone,

    The Huntington Toyota dealership in Long Island, kindly took me immediately yesterday, and they wrote down the issue as "Customer states that 1 week ago gas pedal stuck down - check". The response on the paperwork is "Could not verify complaint at this time found floor mat not on hooks and resecured mat". This was a no charge visit which was nice.

    So the upshot is, nothing wrong with the gas pedal, and the rubber Prius mat was secured (I never saw that there was a way to secure the mat, so I learned something). Although I checked the mat immediately after this happened and the mat didn't seem close to the gas pedal, I agree anything could be true and now it's secured so I feel good.

    I get my usual 6 month maintenance in June 2009 so I will report back if something else occurs but I'm confident this is the solution.

    Again, thanks for listening and explaining so much.

    I'm going for a drive on this beautiful 60 degree sun-shining Long Island day -- have a great weekend everyone.

    Karen
     
    #17 kfetty, Mar 28, 2009
  18. harper42

    harper42 Member

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    In the drive-through at a local restaurant: this has happened a few times.... I sit there with car in park, and it Jumps like it's going to go forward. Scared my granddaughter! But I had experienced it before and knew it wouldn't really move. What's happening here?
     
    #18 harper42, Aug 15, 2011
  19. jdcollins5

    jdcollins5 Senior Member

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    This usually happens when the gas engine (ICE) starts while in Park. This is just the engine taking up the slack between the parking pawl and the gears. You do not feel this in other cars since the engine does not start and stop like the Prius.

    You can check this yourself by pushing the car forward or backwards to see how much movement there is in the parking pawl.
     
    #19 jdcollins5, Aug 15, 2011
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