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The incredible farting ABS pump

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Ianmeister, Nov 11, 2020.

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  1. Ianmeister

    Ianmeister Active Member

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    So I'm in the process of going through a recently acquired 2011 Prius II with 227K miles. The PO said he had the ABS system flushed.... a loaded statement that made my arm hair stand up. So it has started making a little farting noise. After a fairly firm stop I lift up the pedal and hear an obvious PPPPPPT! from the pump. sometimes it does it after I shut off the car and am just walking away.

    Should I source a new pump?
     
  2. ChapmanF

    ChapmanF Senior Member

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    First check the calibration ID of the firmware in the brake ECU. See T-SB-0363-10, which announced an update to avoid making the fart noise. Assuming you have the 15 inch wheels (expected for a II), the updated calibration ID is F152647108.

    If yours is earlier than that, you can ask a dealer to update it. Mine got quieter when I did that.

    If yours continues to fart/honk/bark/squawk and the firmware is at the right revision, if it were mine I would go through the Techstream bleed procedure, the longer option that also bleeds the head-end stuff. There may be a gas bubble hanging out in there.

    If even that doesn't make the honking go away, you can think about replacing the hardware.

    When you shut off the car and walk away, you might be hearing the normal self test. It happens a couple minutes after you shut the car off, so if you've been sitting in the seat catching up on phone messages or something before walking away, sometimes you hear it.

    Normally it shouldn't have loud fart noises, but the normal self test does sound like a series of little clicks and squirts. Sometimes the pump runs.
     
  3. Ianmeister

    Ianmeister Active Member

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    I know what you mean about the little chatter noise. It makes it right when you get in with a key, then again as you're just getting out. This is much louder and shorter, like purse your lips and blow a one second rassberry. 4 out of five times I do a firm stop, then little up on the brake "PBBBBT!"
    I'll talk to my prius guys out here and see what we can do.
     
  4. ChapmanF

    ChapmanF Senior Member

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    The "little chatter noise" right when you get in is the pump itself running.

    The normal self test only happens when you power the car off. It's not right when you get out of the car; there's about a two minute delay. So if you have turned the car off but you're still sitting there catching up on messages or something, you might hear it sometimes. It's a series of little clicks and squirts. Sometimes it will also include the pump sound, but not always.

    For a pronounced fart/bark/honk/squawk sound, see the earlier steps in that last post.
     
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