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Key fob not working (not battery or key button under dash)

Discussion in 'Gen 2 Prius Technical Discussion' started by Prius_in_Lubbock, May 21, 2024.

  1. Prius_in_Lubbock

    Prius_in_Lubbock New Member

    Joined:
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    Location:
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    Vehicle:
    2008 Prius
    Model:
    Four
    Hi all,
    I'm trying to help my dad with his 2008 prius. He had some work done to it by a shade tree mechanic that required the dash to be removed to access what needed fixing (something with the air servo behind the gas pedal).

    Anyway, since the car got put back together the proximity unlocking, fob button locking / unlocking, and the proximity starting no longer work (you need to use the valet key to open the doors and the fob needs to be inserted to start the car).

    There was a code of B2799 that was thrown but it doesnt really tell me anything that I understand nor do I have any idea when it was thrown.


    Things to know
    - It is not fuse #7 in the drivers fuse box
    - The car starts just fine when the fob is in the receptical
    - New and fully healthy 12v battery
    - The fobs light turns red as soon as you push any of the buttons and a fresh battery was put in the day after the mechanic did the work.
     
    #1 Prius_in_Lubbock, May 21, 2024
  2. bisco

    bisco cookie crumbler

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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
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    Plug-in Base
    sounds like the mech accidentally knocked something loose, or forgot to reconnect a harness.
    it might be helpful to use autel or tech stream to look for sub codes, idk.
     
    #2 bisco, May 21, 2024
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Location:
    Columbia, SC
    Vehicle:
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    Model:
    Touring
    You mentioned that you believe the problem is NOT the KEY button under the dash. This button must be in the OUT position for the SKS system to work. Perhaps the mechanic forgot to insert the cars wire harness plug into the back of the button when assembling the dash? It would be worth checking, and also verify the TPMS button is plugged in.

    I'm pretty sure it's a two wire plug, but I'm not certain how it's set up for the contacts to be open or shut when the button is in or out.
     
    #3 TMR-JWAP, May 21, 2024
    Last edited: May 21, 2024
  4. Tombukt2

    Tombukt2 Senior Member

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    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    When working on that servo circuit that determines where the air comes out of the dash feet face etc you are right there where the buttons in question would have to be unplugged and that panel removed and set down somewhere to access to even see the servo that's being discussed I do believe I have a car sitting here with most of those dash pieces out just so I can see things and all of those things are undone at this level of disassembly It sounds like something's just not been plugged back up and to see that you're going to have to move that panel reach behind that panel feel that there's not a plug inserted into the switch that's marked key see if you can find that little black or white plug only one of them will insert into the receptacle on the back of the button and get it plugged up and see if this changes anything there could be other things unplugged I'm not sure exactly what they would be that would just involve the proximity sensing He didn't have the dash top off and probably didn't mess with the SKS blue or black box whatever it is up there on top of the dash just under the dash top. So more than likely it's something right there that he did have to disassemble to work on the servo
     
    #4 Tombukt2, May 22, 2024
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