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2008 Prius keyfob light blinking intermittently without pressing button

Discussion in 'Gen 2 Prius Main Forum' started by domomatic2001, Nov 6, 2017.

  1. domomatic2001

    domomatic2001 New Member

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    We've a 2008 Prius, with two keyfobs. One is working perfectly, the other is having issues which perhaps this forum can assist with. Both fobs have new batteries btw.

    Without any buttons being pressed, the red light on the fob intermittently starts blinking at what appears to be different rates and for different durations. It also seems like the lock button is being pressed, but I can't tell for sure. If I stand next to the car, and press the unlock button, it sometimes works, but sometimes the does nothing and the red light blinks 10 times before I the unlock button can be used again. If I press the lock button, and then quickly the unlock button, I can get into the car without waiting for the ten blinks. Sometimes, standing next to the car after unlocking it results in the car immediately getting locked repeatedly, without me pressing the lock button.

    The other key fob works perfectly.

    I suspect the malfunctioning fob is simply defective, due perhaps to part of the cover over the buttons having broken down over years of use, and something getting into the pcb and shorting something perhaps. Before I get a replacement, are there any final things I can try to get it working ?

    Thanks in advance!

    Dom
     
    #1 domomatic2001, Nov 6, 2017
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Had a similar situation with one of my son's fobs. He has a 2005. The rubber had worn off the buttons and allowed dust/dirt etc to get inside, making the buttons stick. Disassembled and cleaned it. All the weird problems went away, including where his alarm would just randomly sound. Bought a new FOB cover off ebay for a few dollars and swapped all the internals to it. Including the RFID chip a few days later when we realized it had been forgotten about.
     
    #2 TMR-JWAP, Nov 6, 2017
  3. domomatic2001

    domomatic2001 New Member

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    Thanks - yes the rubber has worn out around the buttons. Before I posted this thread, I had taken the fob completely apart and cleaned the circuit board and buttons, but the problem persists. I'm wondering if this fob is toast at this point.
     
    #3 domomatic2001, Nov 6, 2017
  4. domomatic2001

    domomatic2001 New Member

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    Can anyone recommend where to buy a new replacement key fob ?
     
    #4 domomatic2001, Nov 6, 2017
  5. bisco

    bisco cookie crumbler

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    usually eBay from what i've read. you have to make sure you get the correct fob, and a virgin.
     
    #5 bisco, Nov 6, 2017
  6. ChapmanF

    ChapmanF Senior Member

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    This is starting to sound complicated. Can you get both from the same eBay store?

    -Chap
     
    #6 ChapmanF, Nov 6, 2017
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  7. bisco

    bisco cookie crumbler

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    only if you know where to look.;)
     
    #7 bisco, Nov 6, 2017
  8. dolj

    dolj Senior Member

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    +1 to this, the cheapest way to go ...
    ... if you can get the sticking button unstuck. There was a reply to a similar post from an electronics tech who suggested to soak the circuit board in a bath of 90% isopropyl alcohol for a few minutes, without the battery in place, then blow it off with compressed air and let it sit overnight. I would activate both buttons several time over several occasions to ensure it cleans the switch mechanism, while it was soaking – this might make it several minutes rather than a few minutes, though.

    Hope that helps.
     
    #8 dolj, Nov 6, 2017
  9. Fredsimm

    Fredsimm Active Member

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    If you do manage to repair the electronics, you can buy the shells cheaply on ebay. I've replaced 2 shells successfully. You must remember to transfer the small imbedded chip.
     
    #9 Fredsimm, Nov 9, 2017
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  10. domomatic2001

    domomatic2001 New Member

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    Thanks - I brought a used key on eBay, and have programmed it to start the car. How do you program it next to lock/unlock the car too ?
    Dom
     
    #10 domomatic2001, Nov 14, 2017
  11. domomatic2001

    domomatic2001 New Member

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    I took the key to a locksmith who has the appropriate diagnostic/programming device. However, they tried 5 times to reprogram the used key but were unable to. They suggested buying a new key and trying that, but weren't able to tell me if it was the car or the key that was the issue. Any suggestions from the collective mind here? Thanks again in advance.
     
    #11 domomatic2001, Nov 16, 2017
  12. iron-icman

    iron-icman Member

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    I have this same issue, can I just buy a casing off eBay and swap it all over and use my key from my old one and put this in the new one. Will I have to link it to my car or will it be ok because it’s the same internally
     
    #12 iron-icman, Nov 5, 2022
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    Yes, key fob cases are cheap. remove the physical key from the old fob, disassemble it. Sometimes it's going to be destructive to get it apart. Install the circuit board in the new fob. Remove the RFID chip from the old fob and install it in the new one. May need to use a drop of rtv or something similar to hold it in place. Assemble the new cover. Should work perfect. No programming/etc needed.
     
    #13 TMR-JWAP, Nov 5, 2022
  14. ColoradoCrow

    ColoradoCrow Active Member

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    Anyone have a picture of what the rfid looks like inside the Fob?
     
    #14 ColoradoCrow, Nov 6, 2022
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  15. iron-icman

    iron-icman Member

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    #15 iron-icman, Nov 6, 2022
  16. TMR-JWAP

    TMR-JWAP Senior Member

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    New owner of 2004 Prius | PriusChat

    There is a photo of an oem fob. The upper area has the RFID chip. A bit like a rectangle with one corner clipped off. It will have a number printed on it, sometimes hard to see.
     
    #16 TMR-JWAP, Nov 6, 2022
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  17. iron-icman

    iron-icman Member

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    I think this happened to mine how did you clean it all I have taken your advise and purchased a new cover just want to make sure it’s clean before hand
     
    #17 iron-icman, Nov 6, 2022
  18. TMR-JWAP

    TMR-JWAP Senior Member

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    I used rubbing alcohol and an old toothbrush
     
    #18 TMR-JWAP, Nov 6, 2022
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