Incessant honking + red triangle of death

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Alex H, Sep 8, 2025 at 6:34 PM.

  1. Alex H

    Alex H New Member

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    Location:
    New York, NY
    Vehicle:
    2008 Prius
    Model:
    Touring
    My 2008 Prius is honking incessantly. It's a really weak, pathetic, but very-much-there, constant horn blowing. I live in NYC with street parking, so I was parked a block from home and just happened to walk past it (definitely made friends with the neighbors over this), so I have no idea how it was going on. I was able to turn on the car (still had enough juice to start), but found a red triangle of death when I turned it on. It continued honking, even with the car turned on, so I unplugged the battery. Based on some other recommendations here, I changed the 12v battery, but unfortunately the honking continues, and now the car won't start. Has anyone experienced anything like this, and any suggestions before I tow it in to a shop?

    It only has about 120,000 miles, and I'm the only owner, but outside life has been rough for this one.
     
    #1 Alex H, Sep 8, 2025 at 6:34 PM
  2. PriusCamper

    PriusCamper Senior Member

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    Vehicle:
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    I suspect blasting your steering wheel with compressed air would be a good first step to deal with the horn. Then inspect the physical horn and wiring... As for red triangle, there's a chance that low 12volt from honking so much would cause that. But likely something different and not related.

    If you get one of these devices you can read and clear the error code that likely got stored when that red triangle showed up by using a phone app like Dr. Prius: http://www.ebay.com/itm/265484403768
     
    #2 PriusCamper, Sep 9, 2025 at 8:15 PM
  3. Tombukt2

    Tombukt2 Senior Member

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    How about to start just unplugging the horn? Then you can use a test light in a fixture to test that horn still active . Then play with horn button pad . Is the alarm or Immo active ?
     
    #3 Tombukt2, Sep 9, 2025 at 8:54 PM
  4. PriusCamper

    PriusCamper Senior Member

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    If only I knew what a "horn button pad" was and I'd make it my first tattoo.
     
    #4 PriusCamper, Sep 10, 2025 at 12:10 AM
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