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Intermittent Brake/ABS light & mushy brakes

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by cbird02, Mar 26, 2023.

  1. cbird02

    cbird02 Junior Member

    Joined:
    Mar 4, 2020
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    Location:
    Tucson, AZ
    Vehicle:
    2009 Prius
    Model:
    LE
    I am having an intermittent problem with my brakes or the electronics that control them. The car will have no problems, then usually after being shut down and turned back down(not every time) the brake light and ABS light will come on and the brakes will be mushy and weak but not gone completely. I found a hack, that you can turn off the car, and short two pin holes on the ODB(top #4 to bottom #5) with a paperclip, turn on the car and pump the brake pedal 8 times very fast, turn the car off. You then remove the paper clip and turn on the car and the lights are gone/brakes work. I am trying to find out what the root cause of this is. It has not happened while driving, but it did happen once when I stopped for a curb side grocery and just put it in park without turning the car off. Any ideas?
     
    #1 cbird02, Mar 26, 2023
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
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    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    So when the lights are on and things are not happening as expected why is no one trying to read codes The light is generally on because the computer has seen something that it does not appreciate electrically. So usually we start scanning the system the 20 computers in the system or so for codes to get deep into these computers it takes some well designed software made by several companies If you don't have that many times you're scan tool will show nothing and what have you and you think everything is great and you have no codes but yet you have lights on the dash there's a reason those lights are on on the dash and it's not just to illuminate some LEDs. They're there because there is something stored in systems eProms or something and somebody needs to get that data out so they can make proper diagnostics You will see threads here with people swear up and down they have no codes and they're right they don't The car does they're not up on how to extract from the car and therefore they have no codes to them
     
    #2 Tombukt2, Mar 26, 2023
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
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    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I love how often people "find the hack" for getting the trouble codes to find out what the root cause is, and then only use it to clear them. You were this close to finding out why your warning lights were on. Next time you get the chance, you can post the trouble codes here.

    Blink (a/k/a Flash) Codes – How to. | PriusChat
     
    #3 ChapmanF, Mar 26, 2023
    Tombukt2 likes this.
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