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Beep when braking

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by mrstop, Jul 4, 2018.

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  1. mrstop

    mrstop PWR Mode

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    Lately, when coming to a stop my car has started beeping at me. If I pay attention to the display, a message flashes but goes out too quickly to read. I checked the engine oil level and it is full.

    Any ideas what might be causing the car to beep at me?
     
    #1 mrstop, Jul 4, 2018
  2. bisco

    bisco cookie crumbler

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    maybe a bad brake actuator. check the brake fluid level.
     
    #2 bisco, Jul 4, 2018
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  3. Raytheeagle

    Raytheeagle Senior Member

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    Is this intermittent or every time you come to a stop?
    Anyone ridden in the car and tried to help read the message?
    Is it for abrupt stops only?
    Have a code reader that might be able to help?
     
    #3 Raytheeagle, Jul 4, 2018
  4. Grit

    Grit Senior Member

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    Door or hatch not closed all the way?
     
    #4 Grit, Jul 4, 2018
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  5. ASRDogman

    ASRDogman Senior Member

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    Use a camcorder and record it. Then you can play it back in slow motion or frame by frame and see what it says.
     
    #5 ASRDogman, Jul 4, 2018
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  6. bisco

    bisco cookie crumbler

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    how many miles on her?
     
    #6 bisco, Jul 4, 2018
  7. tankyuong

    tankyuong Senior Member

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    check your 12v battery
     
    #7 tankyuong, Jul 4, 2018
  8. mrstop

    mrstop PWR Mode

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    I checked for codes with my OBDII reader and there wasn't anything showing. It happens intermittently at normal stops. I need to play some more to see if I can replicate circumstances to trigger it. Good idea to film and play back in slow motion as it's too quick for even focused passengers to read.

    70,000 miles on the car. Brake fluid is about 1/4" down from full.

    The car is still the original 12V battery. MPG has dropped quite a bit over the past 6-months so I thought the battery might be a possibility (Although the drop might be more attributable to my daughter and wife driving it more (and on short trips)). I took a quick read of the battery voltage this afternoon and the battery was surprisingly at 12.8V with everything off. I'm going to measure the voltage in the AM after it has sat overnight to check the battery again.
     
    #8 mrstop, Jul 4, 2018
  9. mrstop

    mrstop PWR Mode

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    I checked for codes with my OBDII reader and there wasn't anything showing. It happens intermittently at normal stops. I need to play some more to see if I can replicate circumstances to trigger it. Good idea to film and play back in slow motion as it's too quick for even focused passengers to read.

    70,000 miles on the car. Brake fluid is about 1/4" down from full.

    The car is still the original 12V battery. MPG has dropped quite a bit over the past 6-months so I thought the battery might be a possibility (Although the drop might be more attributable to my daughter and wife driving it more (and on short trips)). I took a quick read of the battery voltage this afternoon and the battery was surprisingly at 12.8V with everything off. I'm going to measure the voltage in the AM after it has sat overnight to check the battery again.
     
    #9 mrstop, Jul 4, 2018
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  10. fuzzy1

    fuzzy1 Senior Member

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    By any chance, might you be pressing hard enough to activate the Hill Holder feature (Hill Start Assist Control, or HAC)?
     
    #10 fuzzy1, Jul 4, 2018
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  11. douglasjre

    douglasjre Senior Member

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    techstream
     
    #11 douglasjre, Jul 5, 2018
  12. Kate M

    Kate M Junior Member

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    Hello, was this ever resolved?

    I just bought a 2013 Prius Two and noticed the same issue.

    Inconsistent beep when I come to a stop sign.

    Quite worried now, as this is a used car and in otherwise great condition.

    thanks
     
    #12 Kate M, Oct 16, 2021
  13. Kate M

    Kate M Junior Member

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    Actually, just listened again, and it’s more like a high-pitched hum that lasts one second. Heard it also when stopping in reverse.
     
    #13 Kate M, Oct 16, 2021
  14. ChapmanF

    ChapmanF Senior Member

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    There is a little electric pump that can run occasionally when you use the brakes. Usually not every single time, typically every few times. You may also hear it when you open the driver door to get in when the car has been parked a good while.

    In any case, it's easy to make that pump run and familiarize yourself with what it sounds like. You can just sit parked and apply and release the brakes repeatedly. Every so many times, you will hear the little buzz of the pump.

    Then, if you get familiar with that sound and it isn't the sound you mean in this thread, we can go back to the drawing board and try to figure this one out.
     
    #14 ChapmanF, Oct 16, 2021
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  15. douglasjre

    douglasjre Senior Member

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    Obd code?
     
    #15 douglasjre, Oct 16, 2021
  16. Kate M

    Kate M Junior Member

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    I'll go into my garage and try that. I drove a 2005 for 16 years so I'm familiar with what "normal" sounds like in that model.
     
    #16 Kate M, Oct 16, 2021
  17. Kate M

    Kate M Junior Member

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    It's a higher pitched, steady, but shorter-lasting sound than the pump.
     
    #17 Kate M, Oct 16, 2021
  18. Kate M

    Kate M Junior Member

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    What's that, please?
     
    #18 Kate M, Oct 16, 2021
  19. ChapmanF

    ChapmanF Senior Member

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    That's an on-board diagnostics code, but you would only have one if the car was reporting a problem, and if you had a way to read the code. I'm not gathering that that's your situation at this point.

    Does any dash light come on with the beep?

    Gen 3 has a "hill start assist" function. If you come to a stop with the brake, and then push the pedal a bit further, there will be a beep and the traction (squiggly road) light will come on. That means the brakes will hold for a couple seconds while you move your foot from the brake to the go pedal.
     
    #19 ChapmanF, Oct 16, 2021
  20. Kate M

    Kate M Junior Member

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    Thanks for explaining. No dash light indicator.
     
    #20 Kate M, Oct 16, 2021
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