1. Attachments are working again! Check out this thread for more details and to report any other bugs.

funny little elec-motor buzzing noise on and off

Discussion in 'Prime Main Forum (2017-2022)' started by The Big Sleaze, Feb 5, 2020.

  1. The Big Sleaze

    The Big Sleaze Member

    Joined:
    Nov 28, 2019
    276
    60
    0
    Location:
    'frisco
    Vehicle:
    2020 Prius
    Model:
    Two Eco
    I notice it after about 30 miles of highway when I come to bridge toll slow down to parking lot crawl speed.

    sounds kinda like an automatic antenna, but shorter duration. keeps happening till I speed up (and can't hear).

    cycles about every 20-30 seconds, lasts about 2 seconds.

    What could it be? happens with HVAC on or off
     
    #1 The Big Sleaze, Feb 5, 2020
  2. m8547

    m8547 Senior Member

    Joined:
    Aug 8, 2018
    927
    615
    0
    Location:
    Colorado
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    It's probably the brake booster. Pump the brakes a couple times while stopped/parked and that will probably trigger it.

    There's also a periodic soft beeping sound that I think comes from the HVAC. Can anyone explain what that is?
     
    #2 m8547, Feb 5, 2020
    Trollbait and FuelMiser like this.
  3. schja01

    schja01 One of very few in Chicagoland

    Joined:
    Apr 22, 2005
    1,732
    1,156
    0
    Location:
    Chicagoland
    Vehicle:
    2018 Prius
    Model:
    Prime Advanced
    “Funny”?
    Funny “ha ha” or funny “strange“?
    Does it “amuuuuse” you?

    Sorry, I couldn’t help my self. Great movie.
     
    #3 schja01, Feb 6, 2020
  4. The Big Sleaze

    The Big Sleaze Member

    Joined:
    Nov 28, 2019
    276
    60
    0
    Location:
    'frisco
    Vehicle:
    2020 Prius
    Model:
    Two Eco
    Oh, I guess since the motor ain't running there is no vac, hence yet another elec. motor. Makes sense, only happens when I'm in bumper to bumper and poking the brakes frequently.
     
    #4 The Big Sleaze, Feb 6, 2020
  5. FuelMiser

    FuelMiser Senior Member

    Joined:
    Jun 29, 2008
    1,268
    860
    0
    Location:
    Monument, CO
    Vehicle:
    2016 Prius
    Model:
    Touring
    The brake pedal is given a vacuum assist to make the pedal easier to push (AKA power brakes). In traditional cars, vacuum is sucked of the intake manifold. But in modern cars, an electric vacuum pump provides the assist. Thus, every time you pump the brake pedal, the vacuum pump operates.
     
    #5 FuelMiser, Feb 7, 2020
  6. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    21,707
    11,305
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    It is actually a pump plus accumilator, that allows the pump to not need to run all the time. Though any engine with a throttle plate will also use that vacuum when available. Aside from full hybrids, diesels, and turbos, a car likely doesn't need this system.
     
    #6 Trollbait, Feb 7, 2020
  7. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,266
    15,065
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    There is no vacuum used in the Prius brake system. There is an electric pump that forces brake fluid into a high-pressure accumulator.

    If you want to count the vacuum downstream of the throttle making the engine hard to spin during engine braking, then yeah, there is that vacuum.
     
    #7 ChapmanF, Feb 7, 2020
    jerrymildred likes this.
  8. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,491
    14,100
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    Ya beat me to it! :)
     
    #8 jerrymildred, Feb 7, 2020
  9. FuelMiser

    FuelMiser Senior Member

    Joined:
    Jun 29, 2008
    1,268
    860
    0
    Location:
    Monument, CO
    Vehicle:
    2016 Prius
    Model:
    Touring
    Okay, I stand corrected. The point is the brake assist is making the noise...
     
    #9 FuelMiser, Feb 7, 2020
    jerrymildred likes this.
  10. m8547

    m8547 Senior Member

    Joined:
    Aug 8, 2018
    927
    615
    0
    Location:
    Colorado
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    The 4runner has been using a similar system since 2003 (and it probably wasn't the first). I'm guessing the electric pump allows more brake pressure to be used for when it automatically applies the brakes for traction control, rather than a vacuum brake booster that might not be able to recharge as quickly.

    Tacomas from the same era used a vacuum brake booster.
     
    #10 m8547, Feb 7, 2020
  11. meeder

    meeder Active Member

    Joined:
    Jul 8, 2019
    239
    161
    0
    Location:
    Doesburg, The Netherlands
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Traction control systems mostly use the ABS pump.
    There are multiple ways of operating. The electric system that Toyota uses is useful since the engine doesn't need to operate.
    Diesel engines and turbocharged petrol engines often use a camshaft driven vacuum pump to provide vacuum.

    Verstuurd vanaf mijn LYA-L09 met Tapatalk
     
    #11 meeder, Feb 7, 2020
    Trollbait likes this.
  12. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,266
    15,065
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Hmm, well, we can say there is a brake assist pump, and it does make a funny little elec-motor buzzing noise on and off.

    So it certainly might be what's making the OP's noise.

    But when saying that's what is making the OP's noise, most of us aren't right there with the OP's car.
     
    #12 ChapmanF, Feb 8, 2020
(You must log in or sign up to post here.)