2010 with buzzing brake pedal while stopped

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Cessna157, Jul 21, 2014.

  1. Cessna157

    Cessna157 Junior Member

    Joined:
    Oct 22, 2006
    25
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    Location:
    Orlando, FL (Walt Disney World)
    Vehicle:
    2010 Prius
    Model:
    II
    Greetings all. Purchased a used 2010 Gen III a few months ago and have noticed a fast buzz, felt through the floor and brake pedal. It is intermittent but the conditions needed are:
    1) Air conditioning running at high speed
    2) Vehicle in Drive
    3) Immediately approaching a stop, and a few seconds after stopping.

    It is definitely not the brake accumulator running. This is a much higher frequency buzz. If the A/C is turned off, or the vehicle shifted to neutral, the buzzing stops. I cannot necessarily feel it while driving as it would be covered by road vibration, but it comes on heaviest just as the vehicle is stopped and lasts for a few seconds then seems to phase in and out.

    Anyone else experience this?
     
  2. Cessna157

    Cessna157 Junior Member

    Joined:
    Oct 22, 2006
    25
    5
    0
    Location:
    Orlando, FL (Walt Disney World)
    Vehicle:
    2010 Prius
    Model:
    II
    Update/resolution: It is a known issue! Just took Elsa to the dealer today and described the problem as I have here. When I got her back the advisor said they updated the brake and ABS software to a newer version and it should greatly dampen, but not eliminate the noise. Drove 30 miles this afternoon and didn't notice it at all, so I'd call it a success.

    My service invoice reads:
    "EL1034 REFLASH BRAKE ACTUATOR SKID CONTROL ECU"
    "Noise caused by brake accumulator building pressure. EL1034 recalibrate ABS ECU with updated software to reduce brake noise"

    The only thing that confuses me is the noise itself wasn't coming from the accumulator. When it would make the noise I pumped the brakes to try to isolate the noise, but while I heard/felt the buzzing I also heard the accumulator activate to recharge the brakes from the pumping.

    But alas, no more noise. Hope this helps!
     
  3. GregP507

    GregP507 Senior Member

    Joined:
    Apr 5, 2014
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    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I think the buzzing originates in the inverter, which converts DC current to AC. I don't think it does any harm. I think it's part of the Prius experience.
     
  4. boochi101

    boochi101 Junior Member

    Joined:
    Apr 18, 2010
    27
    0
    0
    Location:
    South Florida
    Vehicle:
    2010 Prius
    Model:
    IV
    I have the same buzzing issue with my 2010 prius 100K miles too. I approached my local toyota dealer and they confirmed the above EL1034. But they want $100 to do software update. Isn't the software update free? Dealer says it is only free within 3 year 36000 miles.

    Does calling toyota help to get the software update free?
     
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