On Going FOB Problems

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BrandonNR, Jun 19, 2021.

  1. BrandonNR

    BrandonNR New Member

    Joined:
    Jun 19, 2021
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    Location:
    Arizona
    Vehicle:
    2009 Prius
    Model:
    II
    Hello,
    I have a 2009 Prius and have had on going problems with my key fobs.

    I bought the car off my dad a few years ago and right after I bought it I had some issues. The 12v battery died (the car alarm would also randomly go off and the mfd stopped working so I can't see the battery's charge). I charged the battery and it drove pretty much smoothly from there. At the same time as my battery died; my key fob stopped working. At first I just thought it had something to do with the car battery, but after I got it charged the fob still didn't work. So I changed the fob battery (not knowing it has to also be reprogrammed). And the buttons didn't work. I asked my dad about it and he gave me his spare and took my non working fob. I've long since forgotten about the non working fob because it's been three years and I've had no problems.

    Until a few days ago. The buttons stopped working on the spare (but would still work to open the door keyless and would still start the car in or out of the slot) and the car alarm started randomly going off again too. I read on a thread that the alarm can go off if it's not getting a signal from the fob. So I assumed that the battery was dead in the fob. I changed the battery in the fob last night and surprise surprise... The buttons still don't work. But BOTH fobs still let me in the car keyless and both can still start the car. I thought maybe it was the case/ membrane for the buttons but when I was testing out the keys in the car after changing the batteries; the car alarm went off again. I've already decided that the unlock/lock buttons weren't all the necessary and that I could just manually lock the door from now on but why would my car alarm still go off?

    I'm lost as to what the problem even is. Is it the 12v battery? Do I need new cases for the fobs? Do they need to be reprogrammed? I'm unsure if the fobs even need to programmed considering they still can do keyless functions. Should I even try to do the "Chicken Dance" if both keys' buttons don't work?
    I'm mostly worried about putting money in the wrong solution, as it's pretty tight right now because I had surgery recently.

    Thanks in advance for any advice!
     
  2. bisco

    bisco cookie crumbler

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    make sure none of the buttons are stuck, and test/charge/replace the 12v
     
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  3. davecook89t

    davecook89t Senior Member

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    Possibly. Have it tested, as has been suggested.

    Possibly, but don't buy new cases until you are sure the 12V is not causing the problem, and if you do buy new cases, be sure to transfer all the electronics over from the old ones. In fact, don't throw the old cases away until you are sure the new ones are completely functional, in every aspect. Apparently, it's easy to miss one particular chip that needs to be transferred and failing to do so will prevent any functions from working with the new case.

    No.

    No.
     
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  4. BrandonNR

    BrandonNR New Member

    Joined:
    Jun 19, 2021
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    Location:
    Arizona
    Vehicle:
    2009 Prius
    Model:
    II
    Update:
    I had my 12v battery checked and it's still good (I'm actually a little surprised).

    I'm going to clean both fobs and hope that it's just stuck buttons or dust/debris that causing my problem.
     
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