Clicking sound from gas tank area when brakes are pressed or car turned on or off

Discussion in 'Gen 2 Prius Main Forum' started by J Leonard, Apr 14, 2024.

  1. J Leonard

    J Leonard Junior Member

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    Hello All,
    A have a 2008 Prius new to me. It makes a clicking sound from seemingly on top of the gas tank. at first I thought it had something to do with the gas tank (I have had to replace 2 of my 2009 prius gas tanks). However, I eventually noticed that the clicking sounds occur at key near car before ignition on, when sitting stopped with brake pressed, and after ignition off for up to several minutes. I have replaced about six actuators and this isn't that. Eventually after several weeks of driving it produced a C1391 loss of pressure code. When I cleared it with techstream the clicking sounds got a lot quieter but still there. It almost seems as if there is some sort of brake pressure relief valve on top of or near the gas tank but I have no idea if this is even a thing.
    Help. An no this isn't actuator noise from up front. I have the back panels and seats removed as I had to replace the hybrid battery after purchase land can hear the noise seemingly on top of the gas tank. I would thing some sort of evaporative purge noise from something failing (which would have been annoying as I discarded the old tanks after replacement). It is clearly linked to brake pedal pressure when stopped as at a light. No sound during mnormal driving. And lifting foot to barely stopping does lessen or stop the sound.
     
    #1 J Leonard, Apr 14, 2024
    Last edited by a moderator: Apr 16, 2024
  2. ChapmanF

    ChapmanF Senior Member

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    I'm drawing a blank on your noise. "brake pressure relief valve" isn't a thing.

    But I did notice you spelled C1391 with a P. If you still have the Edit button available for your post, you can fix that, and then it won't be a distraction to other readers (and searches will group it correctly with other posts about the same code).
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Maybe bleed the rear brakes relay stay in person sits in the car hold the pedal down the pump does the work I bet there's some air back there on the passenger side rear.
     
  4. J Leonard

    J Leonard Junior Member

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    Yes, got the letter wrong. I had a hard time finding out how to even post the thread. No edit button that I see. It was in fact a C1391. Edit button here naturally :}
     
    #4 J Leonard, Apr 15, 2024
    Last edited by a moderator: Apr 16, 2024
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    I fixed the post to change it to C1391.