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

2009 Yellow Brake Warning Light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ridge_Prius, Sep 23, 2020.

  1. Ridge_Prius

    Ridge_Prius Junior Member

    Joined:
    Sep 23, 2020
    2
    3
    0
    Location:
    New York
    Vehicle:
    2009 Prius
    Model:
    Two
    2009 Prius with 120,000 miles. I have a yellow Brake Warning light on. (exclamation point in a circle and parentheses). My brakes are operating normally. Shoes and pads are good. No leaks. Fluid level is correct. Parking brake works fine. All brake lights are operational. I tried the paper clip jumper reset. The tire inflation light is on also ever since I changed from my winter tires, although the pressures are correct. I thought this might be one of the inflation valve sensors. Anyone have a similar situation or know of a solution?
     
    #1 Ridge_Prius, Sep 23, 2020
    Longinus876 likes this.
  2. SFO

    SFO Senior Member

    Joined:
    Feb 7, 2017
    5,301
    4,238
    0
    Location:
    Northern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    #2 SFO, Sep 23, 2020
  3. Ridge_Prius

    Ridge_Prius Junior Member

    Joined:
    Sep 23, 2020
    2
    3
    0
    Location:
    New York
    Vehicle:
    2009 Prius
    Model:
    Two
    The connector to the Brake Control Power supply, next to the 12v battery, wasn't clicked in all the way. That fixed it.
     
    #3 Ridge_Prius, Sep 24, 2020
    Longinus876 and SFO like this.
  4. SFO

    SFO Senior Member

    Joined:
    Feb 7, 2017
    5,301
    4,238
    0
    Location:
    Northern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    Odd. Wonder how that could've happened?
     
    #4 SFO, Sep 25, 2020
    Longinus876 likes this.
  5. Longinus876

    Longinus876 Junior Member

    Joined:
    Feb 7, 2017
    96
    6
    0
    Location:
    Long Island
    Vehicle:
    2005 Prius
    Model:
    N/A
    What does that box do anyway?
     
    #5 Longinus876, Aug 29, 2023
  6. Longinus876

    Longinus876 Junior Member

    Joined:
    Feb 7, 2017
    96
    6
    0
    Location:
    Long Island
    Vehicle:
    2005 Prius
    Model:
    N/A
    I have the same problem with that light being on.
     
    #6 Longinus876, Aug 29, 2023
  7. Longinus876

    Longinus876 Junior Member

    Joined:
    Feb 7, 2017
    96
    6
    0
    Location:
    Long Island
    Vehicle:
    2005 Prius
    Model:
    N/A
    Now is that done?
     
    #7 Longinus876, Aug 29, 2023
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,860
    16,184
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    It makes sure the brake-by-wire system still has electrical power for a while if there is a failure of the rest of the electrical system.
     
    #8 ChapmanF, Aug 29, 2023
  9. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,654
    1,693
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    What codes do you have in the ABS ecu? (there are many codes that can turn the warning light on- knowing what one you have makes for much less guessing).

    Posted via the PriusChat mobile app.
     
    #9 mr_guy_mann, Aug 29, 2023
(You must log in or sign up to post here.)