Vibration when Coasting

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Christopher De Leon, Nov 25, 2015.

  1. Christopher De Leon

    Christopher De Leon Junior Member

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    Location:
    San Antonio, TX
    Vehicle:
    2009 Prius
    Model:
    II
    Symptom:
    A vibration that feels somewhat like a bouncing tire

    Cause:
    Coasting in Drive (Applying the gas at all stops the vibration, putting the car in Neutral also stops the vibration)

    Any idea what this could be?
     
    #1 Christopher De Leon, Nov 25, 2015
  2. bisco

    bisco cookie crumbler

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    if it was a tyre, wouldn't it remain while coasting in neutral? how many miles on her?
     
    #2 bisco, Nov 25, 2015
  3. Christopher De Leon

    Christopher De Leon Junior Member

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    I didn't mean to say that I thought it was a bouncing tire, but that's what the sensation feels like.
    125k Miles
     
    #3 Christopher De Leon, Nov 25, 2015
  4. andrewclaus

    andrewclaus Active Member

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    Check the engine mounts.
     
    #4 andrewclaus, Nov 26, 2015
  5. bisco

    bisco cookie crumbler

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    any difference with engine running or not?
     
    #5 bisco, Nov 26, 2015
  6. Christopher De Leon

    Christopher De Leon Junior Member

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    I was again testing last night, and it seems to be vibrating (though less) when I touch the gas still. However it does go away when I press the gas more. This IS starting to sound like an engine mount problem, as I hear, engine mount problems can go away with engine load as the torque of the motor can hold it in place, but when idle or low load the engine is free to vibrate.

    The only thing is, how does this explain the vibration when the engine is off altogether?
     
    #6 Christopher De Leon, Nov 26, 2015
  7. andrewclaus

    andrewclaus Active Member

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    I suppose the transaxle is still being driven by the axles, and that's attached to the engine? Not sure. There's still some braking torque going on in the transaxle with the engine off.
     
    #7 andrewclaus, Nov 26, 2015
  8. bisco

    bisco cookie crumbler

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    when you touch the gas, does not mean the engine comes on. you need to do more testing and differentiate.
     
    #8 bisco, Nov 26, 2015
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