Traction control, abs light, and yellow (!) And code#0129

Discussion in 'Prius v Main Forum' started by Bradley S Stearns, Nov 21, 2021.

  1. Bradley S Stearns

    Bradley S Stearns New Member

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    Just happend a few days ago, took it to the dealer and they said the only code that came up was a u0129, lost communication with break system control module (BCSM). the lights are intermediate never know when they are going to come on. I changed the breaks recently could that have anything to do with it? When driving it doesn't seem anything is wrong.
     
  2. Bradley S Stearns

    Bradley S Stearns New Member

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    I'm on a road trip so any help would be great.
     
  3. ChapmanF

    ChapmanF Senior Member

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    That U0129 is not a very common code. It means something has lost the ability to communicate with the brake ECU.

    It might not be hard or expensive to fix, depending on what the communication failure turns out to be, but it seems pretty likely that something won't be working right meanwhile.

    As with many of the Uxxxx communication codes, it matters which ECU in the car reported the U0129. The power management control ECU, the combination meter, the steering ECU, and the parking assist ECU if you have that, all communicate with the brake ECU, so any of those could be the one saying "U0129 hey I can't communicate with it."

    A good scan tool like Techstream will show the codes grouped by whatever ECU in the car reported them. Some other tools just show you a bunch of codes they retrieved but not which ECUs they were retrieved from.
     
  4. rjparker

    rjparker Senior Member

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    Seems the dealer might have more detail as Chap suggests. Perhaps a phone call tomorrow. Unlikely the brake job caused it.
     
  5. Air_Boss

    Air_Boss Senior Member

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    Poor, intermittent or lost connection to an ABS wheel sensor? Separate, clean and reinstall the pigtail/whip connectors.
     
    #5 Air_Boss, Nov 22, 2021
    Last edited: Nov 22, 2021
    gromittoo likes this.
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