Hazards blinking faster as car accelerates 2012 Prius

Discussion in 'Gen 3 Prius Technical Discussion' started by Breathe54, Sep 8, 2021.

  1. Breathe54

    Breathe54 New Member

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    Just bought a well maintained 2012 Prius and when I drove the hazards blink faster and faster as I accelerate. Haz switch won’t turn them off

    a few blog posts suggest the skid control ecu… can this be purchased used and would dealer need to calibrate?

    any other suggestions! I’m going to disconnect the skid control ecu to see if prob stops

    thanks
     
  2. PriusCamper

    PriusCamper Senior Member

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    That's a weird problem... Never heard of it before... Can you get someone to ride with you to confirm it's speeding up, or can you post a link to a video?
     
  3. ChapmanF

    ChapmanF Senior Member

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    That has been a surprisingly common (and a bit comical) failure on third gens.

    Take a look at this post.

    There are two signals that are getting crossed, that happen to be on pins right next to each other in the connector on the skid control ECU.

    People have been fixing by replacing the whole actuator assembly (which includes the ECU), which of course is the only way Toyota would do it.

    If it ever happens to me, I'm pretty sure before I go there I'll try just (a) unplugging and replugging that connector, (b) unplugging it and looking very closely for signs of corrosion or whiskers bridging those two pins that could be cleaned off, (c) trying to see if I could remove the ECU circuit board from the side without disturbing the rest of the unit or the hydraulic connections, and looking closely at the board for similar conditions.

    Before trying (c), I might try to find a used busted actuator assembly I could buy for cheap, and experiment with whether it can be opened up around the circuit board without damage. Sometimes it's good to have one to practice on.

    The access on that side of the unit is not very good, when it is in place in the car.
     
  4. PriusCamper

    PriusCamper Senior Member

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    Those pesky electrons, why can't they behave?
     
  5. ChapmanF

    ChapmanF Senior Member

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    At least they're predictable ... put them in a field, and they follow it wherever you let them.
     
  6. PriusCamper

    PriusCamper Senior Member

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    Or at least we have an atmosphere protecting us from most of the radiation that can flip bits. Off world computer code / no atmosphere has to account for lots of bit flips, aka: Single Event Upset (SEU).

    Three minutes into this video you get the problem explained quickly. It once caused a passenger airplane to fall out of the sky...

     
    #6 PriusCamper, Sep 8, 2021
    Last edited: Sep 8, 2021
  7. ChapmanF

    ChapmanF Senior Member

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    Also, the more you know about an electron's momentum, the less sure you can be of where it is.

    But I think Breathe54's hazard lights are blinking for much less esoteric reasons.
     
  8. PriusCamper

    PriusCamper Senior Member

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    Yep... And look at it even closer and you'll realize that it only exists because you're observing it...
     
  9. ChapmanF

    ChapmanF Senior Member

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    Well, its very existence may not depend on whether you looked, but if you looked closely enough to say it's here, you did stop it from being there. Where it might, otherwise, have been.

    But the blinking hazards can probably be fixed without any resort to cosmic rays, Planck's constant, etc....
     
  10. Brnstrmr

    Brnstrmr Junior Member

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    Talk about ADD.
     
  11. Brnstrmr

    Brnstrmr Junior Member

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    Mine were flashing sporadically for a couple of weeks. They stopped this week only to give me a strange scraping noise coming from around where the ABS control unit is, plus a Code C1311. Investigating.
     
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