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Well there’s a thing, sudden unintended acceleration just happened to me

Discussion in 'Model 3' started by Marc Roberts, Jun 27, 2020.

  1. MrWattson

    MrWattson Member

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    I had not thought about it but I have driven mainly manual transmission vehicles and the shift to one-pedal was not a big deal to me either. I use the 'hold' setting as well.

    As a manual fan who found too few manual vehicle choices remaining, I skipped a life of CVTs and 10-speed paddle shifting and just went electric. Glad I did.
     
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  2. MP3Mike

    MP3Mike Well-Known Member

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    But it doesn't actually say that.

    Maybe they didn't put all the details in. Try again with actually pushing the brake pedal more and see if it works how they describe it.
     
  3. noobla3

    noobla3 Member

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    I had this happen to me last week.

    I pulled out of a parallel parked space creeping slowly to the red light. I was in the first space before the light and there was no traffic around. As I was so close to the line, I crept forward ever so slightly, feathering the accelerator. I would say speeds were between 0.5 to 1-2 mph. As I lifted my foot off the accelerator, I felt slight regen, then a pronounced lurch. I hit the brake pedal to stop crossing the line by 1/3 car length.

    My setup: Hold mode, Std Regen, Std Acceleration (not chill).

    Absolutely sure: did not bump cruise control stalk, no 2 foot driving, no depressing the wrong pedal (as I had lifted off at the time)

    Condition: sunny dry day. Ever slight slope upward of road toward center lane (standard for drainage proposed, flat road,not hilly)

    I was perplexed and thought about it for like the next 10 minute drive and didn't think about hitting the save on th dashcam.

    I had another incident having to do with clicking noise of the mechanical brakes while also an ultra low feathering speeds.

    I've read all the comments of this thread, and most people take it as user error, but I definitely think there is something weird at ultra low speed while feathering and coming to a stop.
     
  4. KenC

    KenC Active Member

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    You're in San Francisco. Did you have regen dots, indicating your battery was cold and might only have partial regen? If so, it could just be that what you felt is the limited regen. So, regen became less regen, and the car seems to accelerate as the regen becomes less.
     
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  5. noobla3

    noobla3 Member

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    It definitely was not more or less regen as I felt a pronounced lurch forward.
     
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  6. Zextraterrestrial

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    no accelerator has stuck in a Tesla that I have ever heard of, so I doubt that is it.

    Regen thinks your tires are slipping in relation to one another. happens every time I change tires to a different size. have swapped tires probably 100 times on my S and already 20-30 times on my 3

    also if you run over a really slippery spot/ice on just 2 tires or similar you'll get 100% regen drop and it feels like acceleration almost
     
  7. Zextraterrestrial

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    I bet it was hold mode and the stripe. was it damp or cold? thermo is slippery compared to pavement. AWD or RWD?
    if you are just using regen and it hits less traction on the front wheels it will drop a lot of regen if not all
    & I hate hold mode because it does funky stuff w/ the brakes. semi personal thing. mostly left foot brake in Tesla too
     
  8. stopcrazypp

    stopcrazypp Well-Known Member

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    #168 stopcrazypp, Jan 13, 2021
    Last edited: Jan 13, 2021
    NHTSA document doesn't lay out the specifics for when motor power is limited to 50kW. Only that the brake pedal is pressed first.

    Regardless, this feature is obviously for those of us who are used to using left foot braking in certain situations (which I do in my old car and glad the Tesla supports also).

    Could the numbers be different with dual motor vs single motor?

    But as relevant to the unintended acceleration incidents, as long as the full override comes if brake is applied after accelerator, that probably is the main use case that NHTSA is concerned about, as that is really what someone would be doing if their accelerator pedal was stuck for whatever reason.

    If you do the accelerator a long while after the brakes, that usually is a sign you intend to accelerate (an exception to allow for left foot brakers), just limited to less in magnitude by the brakes.

    I guess another test that can be done is if you release the brake and press it again will it override the accelerator that was never released (this is to simulate a situation where someone was left foot braking and their accelerator pedal gets stuck afterwards).
     
  9. xyxx

    xyxx Member

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    its the slightly upward sloping angle that does it for me. We have a drain ditch in the middle of the road which i drive over when preparing to back into my garage. Regen doesnt come to a hold but feathers the accelerator - This has happened to me 3x
     
    • Like x 1
  10. 15Peter20

    15Peter20 Member

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    I had this a few weeks ago. I went for a long drive to investigate it. Air temps were cold, but I’d driven in much colder temps without this issue. In any case, by cold I mean about 8 C or so from memory.

    The regen bar would grow towards max if I drove gently but would rapidly disappear if I gave the car a blast of full throttle and the lack of motor braking really felt scary. If I hadn’t been aware of the problem I could have diagnosed SUA.

    This persisted for a couple of day after I logged a service request. I then called my local SC telling them I felt the car was dangerous. They told me they were remotely investigating and, by that evening it was back to normal. Been fine since.
     
  11. noobla3

    noobla3 Member

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    I think this is it. The ever slight slope causes HOLD mode to prevent roll back by accelerating a bit the split second while I'm slowly releasing the pedal. That split second state might be translated differently / wrongly by Tesla's computer? Hard to explain in words.

    Just my guess based on this experience. I know nothing about how Tesla's regen and hold mode all work programmatically.
     
  12. fiveten

    fiveten Member

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    Service came by yesterday to look at it and a few other issues. The guys answer was that the battery was cold and so regen was limited...I told him I didn't buy that, and in any case there is some type of error if regen is limited and the car doesn't tell me that it is limited. I asked if maybe the new tires I had put on the car right before that drive might have affected it, but he said no.

    It was just a one time thing...so hopefully it never happens again. I still kind of suspect that somehow the accelerator pedal was a bit stuck so it wasn't fully disengaging sometimes when I would lift my foot completely off of it.
     
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