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High Pitch Whirring Sound

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by DenToyPri05, Mar 1, 2015.

  1. DenToyPri05

    DenToyPri05 Junior Member

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    It's been cold, but I've been driving. When I park and power down, I'm hearing a high-pitch sound...like a fàn...it lasts about 10 seconds.

    What is my car doing?
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That sound is produced by the engine coolant heat recovery system pump, which operates upon start up and shut down. It is normal for the pump to operate at those times.
     
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  3. Britprius

    Britprius Senior Member

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    This is the sound of the pump returning hot coolant to the thermos tank. Some pumps get noisy in the cold but it does not affect the performance. If it fails a DTC code and warning light will appear. The car can still be safely be driven in this condition.

    John (Britprius)
     
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  4. valde3

    valde3 Senior Member

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  5. bisco

    bisco cookie crumbler

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  6. DenToyPri05

    DenToyPri05 Junior Member

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    because i'm in a racecar...vroom vroom!!! :)

    you know that on-ramp signal to enter highways? depending on whom I am paired with, I'll either "race" or take it easy. when i'm next to an audi or bmw, i wear my grandma hat; when i'm next to any kind of suv, i whiz ahead...that's turbo. lol
     
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  7. davidls

    davidls Junior Member

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    Hi Patrick,
    I have a 2008 model, in Australia, and this car does not have a thermos. However- I get this whirring sound also. Sometimes I go into the garage and if I open a door, it may start. I wondered if it might have something to do with the key in my pocket, but this is not a smart key. What do you think this noise is? Is it something to do with brake line pressure?
    Thanks,
    David
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi David,

    You are hearing the brake actuator motor running. If the driver's door is opened while the car is IG-OFF, the body ECU communicates this info to the skid control ECU which powers up the brake actuator to build up pressure in the hydraulic system, thus getting the car ready to be driven.

    Another possible noise that you may hear the Prius make after it has been parked for a few hours is that the fuel tank will be pressurized to check for leaks. You may hear a pump running for a brief interval when this test is executing.
     
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  9. Britprius

    Britprius Senior Member

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    Again Patrick the Australian Prius does not have a pump to pressurize it to check for leaks. It is only the North American continent Prius that uses the bladder system with the leak detection.

    John (Britprius)
     
  10. davidls

    davidls Junior Member

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    Ah- thanks Patrick. You're a gem!

    Thanks John for the clarification. Aren't we lucky here down under:)
     
    #10 davidls, Mar 6, 2015
    Last edited by a moderator: Mar 20, 2015
  11. Britprius

    Britprius Senior Member

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    You get the same deal as us in the UK/EU.

    John (Britprius)
     
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