2012 Prius V No Response to Power Button

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Nick Velikonja, Apr 25, 2025.

  1. Nick Velikonja

    Nick Velikonja New Member

    Joined:
    Apr 25, 2025
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    Location:
    Minnesota
    Vehicle:
    2012 Prius v wagon
    Model:
    V
    Hi All,

    I'm working on a friend's vehicle, and we're the last resort for this dead prius thats been at another shop for a month. The story is that the vehicle was stolen (with the key still in it), driven, and then left somewhere. Before they left it, the thieves cut off the start button... We don't know why. My friend soldered the wires back together, but now there is no response to the button at all. However, there is ok voltage ~12v in the starting battery, and the power door locks work.
    Code B2784 is set. They tried another button, same thing. The recertification appears to work, waveform on the CODE and TXCT circuits look like communication. The power source control module also appears to work, as live data shows that it sees the button turning on and off. I havent figured out yet how to test the INDW and INDS circuits.

    What am I missing here? Even without a good key, shouldn't the dash turn on and flash an immobilizer light?
     
    #1 Nick Velikonja, Apr 25, 2025
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,608
    50,826
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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    maybe a fuse blew?
     
    #2 bisco, Apr 25, 2025
    Air_Boss and Brian1954 like this.
  3. Carall

    Carall Member

    Joined:
    Apr 22, 2023
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    Location:
    Harrisonburg, VA
    Vehicle:
    2012 Prius
    Model:
    V
    At one repair shop, their mechanic bought a 07 avalon with the very similar problem. The car sat for several years. The door locks work from the fob key. The start button does not respond at all. He bought a second avalon for parts with almost 300k miles, run and drive. He tried to swap all the computers into a non-working car but nothing changed. Still no signs of life. The owner changed the fuse box under the dash, but still no changes. Checked all the fuses. Swapped the computer on the side of the fuse box in the engine compartment.
    There are 2 indicators on the dash: the door is open and the red key indicator is flashing.
    Stepping on the brake pedal, the start button does not turn green even though the brake lights are on.
    There is no sound that the door is open.
    I've checked all the fuses myself. Checked the grounds, the power supplies on the computers. Everything looks fine. I swapped all the computers into a working car and pressing the start button, a signal beep occurs and a yellow light on the dash comes on telling key not found.
    My guess is that there is still no power somewhere or the communication network is interferenced by something.
     
    #3 Carall, May 7, 2025 at 1:03 AM
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