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    eric1234 Member

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    2010 Prius
    Model:
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    Hi,

    I have recently noticed a vibration that occurs at VERY low speed - such as below 0mph and 1mph, while just starting (or stopping).

    The best way to describe this vibration is that it feels somewhat similar to going over a rumble-strip - but not quite so intense.

    It only happens for a very short time while just starting off (or coming to a stop) - and then goes away. You almost have to try to make it happen. If I try to carefully control the increase of the car's speed, I can -sort of- extend the amount of time that this happens.

    I certainly have to be on the 'look out' to notice this and attempt to make it happen to really identify it. Otherwise, (if I accelerate too quickly i.e.: normally) it just feels like a couple of bumps in the road.

    I think I read on here somewhere something about a breakdown of the winding insulation that provides such an effect? Has anyone else ever experienced something similar? Is there any straightforward way (perhaps with a scan gauge or other tool) to conclusively diagnose this?

    Any other experiences/guidance would be appreciated. Of course, I need to bring it to the dealer, but based on how difficult it is to 'find' this problem (if it is a problem) and how short lived it's effect is - I can imagine that getting the dealer to acknowledge it as a problem will be a challenge.

    Thanks much,
    Eric
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    32kcolors Senior Member

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    This is the ICE coming on and shutting off? It's most noticeable when the engine is cold.
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    eric1234 Member

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    Hi. Thanks for your help.

    In this case, it's not the ICE. The 'vibration' occurs at a very specific speed, while the ICE is off.

    It's sort of like a resonance phenomenon - where it builds as you approach the magic speed, and then tapers off as speed increases above the magic speed.

    In this case, the 'magic speed' is very, very low (less than 1 mph), and the window / range of speeds for which it is noticeable is very narrow. With very much, careful concentration and application of the brake (to maintain the 'magic speed') - the vibration can be made to occur continuously.

    Hopefully this is a bit more information, and a better description.

    Thanks,
    Eric
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    firepa63 Former Prius Owner

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    Since it's a new car and still under warranty, and you can make the vibration occur, take the car back to the dealer for service. As 32kcolors states, the most common cause of low speed vibration is the cycling of the ICE when it's cold.
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    eric1234 Member

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    Thanks for your input. I appreciate your help and guidance. It's definitely not the ICE, and has no relation to the ICE.

    As I said in my original post: "Of course, I need to bring it to the dealer..."

    And, I'm well aware that the car is still under warranty, - but before I go to the dealer, I'd like to gather as much intelligence about this occurrence as possible. I know there are some great resources on here that in some instances may know more than average dealer service techs. I believe that the greatest value will be to start with such resources first.

    I am seeking any input from someone who may have experienced a similar problem and had progress with regard to diagnosis and/or repair - perhaps with regard to winding insulation breakdown, as has been mentioned elsewhere here (although it may not be the same situation) - I think (hope) that winding insulation breakdown may result in a code and warning light.

    Thanks,
    Eric
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    qbee42 My other car is a boat

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    So this happens when you are backing up?

    ;)

    Tom
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    jjlawyer Junior Member

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    I felt the same thing in my 09. Most noticable going up a hill at very slow speed like you say, 1mph or so and only when the gas engine is off. I think it happens more when turning. I think I noticed it on my 10 but not sure.
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    eric1234 Member

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    Hi Tom,

    So far, I have only observed it moving forward. (While progressing slowly in a very long on-ramp line.)

    Oh - now I get your joke - "below 0 mph" should have been "below 1mph" ;-)

    Eric
    1 people like this.
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    eric1234 Member

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    Thanks. I haven't noticed it while turning - but will keep my eye out for it now... In order for it to be more than a very brief blip, I have to control my increase in speed very carefully - it actually takes some effort to make it more noticeable...
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    adamace1 Senior Member

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    My car does this too. I think it it the Electric motors/Trans(ecvt) or what ever they call it. it seems to happen just as the brakes bring the car to a stop and the electic motors are still trying to push the car foward. For a brief moment i notice what your talking about then as the electric motor cut their power the vibration goes away. or when you let off the brake it seems to do it a little untill the car gets moving a little. I think it's normal. Try looking at the screen that shows the car and watch the power flow going to the batteries to the electric motor and see if that helps you pin point when it happens.

    If you don't have alot of miles i'd wait to bring it to a dealer untill it gets worse, or you find out it's just normal. I doubt they will be any help, unless it becomes a big problem.

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