Brief noise minutes after shutoff??

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by prius3G3Fan, Mar 11, 2019.

  1. prius3G3Fan

    prius3G3Fan New Member

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    If I happen to stay in my car a few minutes after I shut it off, I hear this brief - say 0.25 second - crank noise. The sound is like a hybrid of (see what I did there?) the sound made by pulling fast on a handbrake (emergency brake) in an old (and pathetic) Chevy Chevette and the jarring sound of grinding the starter on a car that's already running, but more muted. I don't have a problem otherwise, but I hope to figure this out before the certified used warranty runs out on my 2012 Prius Three with around 50K miles.

    I just dropped off my vehicle at the dealer for diagnosis and I didn't think to record audio. This is my first PriusChat post, so if I should post somewhere else etc., let me know.
     
  2. bisco

    bisco cookie crumbler

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    welcome!

    the sound you're hearing is mg1 turning the crankshaft to position the engine properly for the next start operation
     
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  3. ChapmanF

    ChapmanF Senior Member

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    If it sounds like a few clicks, a squirty sound, and a kind of a buzz, it is the brake system doing its usual self test a few minutes after shutdown. It's been doing that as long as you've had the car, but there's always a first time you notice.

    Longer after shutdown (a matter of hours, IIRC), there can be a blower-y sound from further to the rear of the car, as the fuel tank is pressurized to self-test for vapor leaks.

    MG1 positioning the crankshaft is a new one on me; I don't think I've caught my car doing that.
     
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  4. Grit

    Grit Senior Member

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    Mines does that during cold soak start up, slight forward jerk. Emergency brake engaged lightens the jerk.
     
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  5. prius3G3Fan

    prius3G3Fan New Member

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    Thanks for the replies, folks!!

    I don't have much mechanical expertise, but MG1 turning the crankshaft seems to fit the scenario. I'm going to read up on on that. It's not a "loud" noise but sometimes it's louder than others. Maybe it just depends on how far the parts have to travel to get into position. The variation is what made me wonder if the noise is ever a sign of trouble (e.g. if it gets louder).

    ;-) I would love to see the look on the dealer service advisor's face if I brought my car in and said "I think there's something wrong with my car. I don't hear a few clicks, a squirty sound, and a kind of a buzz and a blower-y sound when my car is off."
    They must have run long with my recall-related firmware update yesterday. He said they didn't hear anything and wondered if I was talking about the 'pin moving into place when I put it into park'.

    Makes me wonder if I need to put a hidden camera on this thing and see what else it does when I'm not around!
     
  6. FuelMiser

    FuelMiser Senior Member

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    Normal. No worries. I often stay in the car when my wife goes to the grocery, and I hear these every time after the car is shut off for a couple minutes.
     
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