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Frequent Rattling Even with Engine Off

Discussion in 'Gen 2 Prius Main Forum' started by RandallG, Jul 20, 2017.

  1. RandallG

    RandallG New Member

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    2008 Prius. Since I bought this car almost 10 years ago, there has been a persistent, frequent rattling noise that seems to originate from just behind (or possibly from within) the hybrid synergy drive. Of late, it has become much more frequent. It happens when I am driving or even when the engine is turned off.

    When I am driving at a constant speed, this rattling, which last for about 3 seconds, occurs about every 8-12 seconds. When stopped it occurs about every 22 seconds. It happens almost immediately when I begin braking.

    Even after the car is turned off, the rattling occurs at very frequent intervals (less then 30 seconds) for up to quite a few hours unattended.

    I have a video of this, but this site won't let me post it. Message me and i'll send you a link.

    Where is this coming from? Is it a part that can be replaced somewhat inexpensively? Anything to worry about?

    Thanks. Any advice is appreciated.
     
    #1 RandallG, Jul 20, 2017
  2. bisco

    bisco cookie crumbler

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    just post 5 quick posts, and then you can upload.

    never heard of anything like it, the video should be interesting.

    it's not the buzzing noise that happens when you first open the drivers door, is it?
     
    #2 bisco, Jul 20, 2017
  3. RandallG

    RandallG New Member

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    I also need to wait one day since I just registered. I posted 4 empty threads. Will attach a link tomorrow if it will let me. Thanks for the quick reply.
     
    #3 RandallG, Jul 20, 2017
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  4. Johnny Cakes

    Johnny Cakes Senior Member

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    The engine off comment is interesting -- any chance this is related to or coming from the a/c blower fan?
     
    #4 Johnny Cakes, Jul 20, 2017
  5. FuelMiser

    FuelMiser Senior Member

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    First, you might try posting in the Gen 2 Forum, the one for your car...apparently you can "Report" this post and the moderator will move it.
     
    #5 FuelMiser, Jul 21, 2017
  6. fotomoto

    fotomoto Senior Member

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    A malfunctioning brake accumulator(pump) will run too often but typically it's not very loud and very difficult to hear while the car is moving. It can't maintain pressure so it runs too often. Mine wasn't any louder than it does when you first open the drivers door.

    Any codes/warning lights?
     
    #6 fotomoto, Jul 21, 2017
    Last edited: Jul 21, 2017
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The brake actuator pump is probably beginning to fail. This is the subject of an extended warranty. I recently posted about getting that pump replaced on my 2007 under that warranty.
    See my post #68 here: Brake Actuator Assem - Warranty Enhancement | Page 4 | PriusChat
     
    #7 Patrick Wong, Jul 21, 2017
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  8. bisco

    bisco cookie crumbler

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    he said it's been doing it for 10 years, and as of late, it's become much more frequent.

    see my last sentence in post #2.
     
    #8 bisco, Jul 22, 2017
  9. RandallG

    RandallG New Member

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    #9 RandallG, Jul 23, 2017
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That is the brake actuator pump, which is located on the firewall. You need to remove the tray which houses the windshield wiper motor for access.

    Are any skid control ECU warning lights on (such as ABS, VSC, ((!)), or BRAKE)?

    Even if no warning lights are on, it is possible that DTC may be logged. Use Mini VCI to see if any are present. If so, your car may qualify for coverage under the extended warranty.

    Otherwise, if you have to replace the pump yourself, you could install a used unit and use Mini VCI when purging air out of the hydraulic system. Consult techinfo.toyota.com for repair manual info, as you do not want to screw up the brake system based upon incorrect repair technique.
     
    #10 Patrick Wong, Jul 23, 2017
    Last edited: Jul 23, 2017
    valde3 and jerrymildred like this.
  11. RandallG

    RandallG New Member

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    Thanks, Patrick. I've been listening to that sound for a long time. I was told it was 'normal' but I should have been more skeptical. I'll look into getting it replaced under an extended warranty.

    Thanks again!
     
    #11 RandallG, Jul 23, 2017
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The presence of the sound is normal but a high repetition of the sound is not.
     
    #12 Patrick Wong, Jul 23, 2017
  13. Tideland Prius

    Tideland Prius Moderator of the North
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    It is ridiculous. How about posting like a normal person instead of posting empty posts?
     
    #13 Tideland Prius, Jul 24, 2017
  14. bisco

    bisco cookie crumbler

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    not unusual for a 9 year old car. as patrick said, it's normal, until it's not.
     
    #14 bisco, Jul 24, 2017
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