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Rubbing Noise in EV or Battery mode

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by [email protected], Nov 6, 2023.

  1. Racerman15@comcast.net

    [email protected] Junior Member

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    2020 Prius LE 18k miles. Excellent condition Except I noticed an unusual, very noticeable rubbing/grinding sound I had not heard before when backing out of the garage in battery mode (engine not running). I tried it both forward and reverse and the noise was the same. The noise is the same with the brakes on a little and also released. The noise seems to be coming from down low at the driver's end of the engine. I tried it in EV mode and it was the same.
     
    #1 [email protected], Nov 6, 2023
  2. bisco

    bisco cookie crumbler

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    are you sure it is not the pedestrian warning system?
     
    #2 bisco, Nov 6, 2023
  3. Racerman15@comcast.net

    [email protected] Junior Member

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    How would I know? I looked up Pedestrian warning system in the owner's manual and I found no reference. I have only had the car for two weeks but I am sure it did not make that noise initially. My Gen 3 did not make that noise. I suspect when I go back to the Toyota dealer I will get some nonsense so I wanted to reach out to Chat first.
    Is there a way to turn off the pedestrian warning so I can confirm that it is what I am experiencing?
     
    #3 [email protected], Nov 7, 2023
    bisco likes this.
  4. BiomedO1

    BiomedO1 Senior Member

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    It sounds like rubbing a wet finger on a crystal wine glass.

    That sound should go away around 15+ mph, that would be the pedestrian warning sound. You probably didn't notice it because of the reverse beeper - it only beeps in the cabin, so it's a bit useless IMHO...
     
    #4 BiomedO1, Nov 7, 2023
  5. Doug McC

    Doug McC Senior Member

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    Look in your owners manual under “Vehicle Proximity Notification System” for a probable explanation.
     
    #5 Doug McC, Nov 7, 2023
  6. bisco

    bisco cookie crumbler

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    a lot of people only notice it after a time. you have to have the right circumstances where it reverberates off of walls like a garage.
    it can't be turned off because it is federally mandated. what year was your gen 3? they started installing them in 2012, but weren't law until 22 or something.

    can you stand next to it while someone slowly drives it?
     
    #6 bisco, Nov 7, 2023
  7. Racerman15@comcast.net

    [email protected] Junior Member

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    I walked with it with the hood open while slowly backing up. Noise is coming from the driver's side of the engine, seems down low.
    I know that finger on glass sound, not very loud. On my 13 I think it was just the hybrid system doing it's noises.
    I am concerned that it might be a mechanical issue and wonder if anyone has had this experience.
     
    #7 [email protected], Nov 7, 2023
  8. rjparker

    rjparker Tu Humilde Sirviente

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    The low speed warning comes from a speaker on the drivers side. It turns off past 16 mph. You could disconnect it but you will get trouble code B1350. You can also manually activate it or adjust the volume with Techstream.

    IMG_3426.jpeg IMG_3427.jpeg IMG_3428.jpeg IMG_3429.jpeg IMG_3430.jpeg
     
    #8 rjparker, Nov 7, 2023
  9. Harters

    Harters Active Member

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    Does it make the noise if the engine (ICE) is running? if not then that is another pointer to the “Vehicle Proximity Notification System” as it does not activate when the engine (ICE) is running.

    Also, in the UK the warning system is louder in reverse than it is going forward, I guess US models are the same? I am glad my model doesn't have it.
     
    #9 Harters, Nov 8, 2023
  10. thomassster

    thomassster Member

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    Is it only during slow speeds? You certain it’s not just your tires rubbing on floor cause that’s what I usually hear when backing out of garage. There’s is also the typical noise the regen brake system makes as well. Does it go away in higher speeds?
     
    #10 thomassster, Nov 8, 2023
  11. bisco

    bisco cookie crumbler

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    it sure sounds like the vpns to me
     
    #11 bisco, Nov 8, 2023
  12. thomassster

    thomassster Member

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    Vpn sounds like those noises you typically hear of alien spacecraft in cartoons or that glass description mention earlier. I wonder if it’s damaged. Vpn is activated during low speeds, and not when stopping. Once you put it in reverse, the noise should start occurring.
     
    #12 thomassster, Nov 8, 2023
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