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Key Fob Battery Questions

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by qdllc, Jan 10, 2017.

  1. qdllc

    qdllc Senior Member

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    I got the key fob battery low warning a few weeks back. Bought two batteries but didn't change them because the warning didn't come back. Then, it happened twice yesterday, so I (1) switched to the other key fob that's sat unused since buying the Prius (2013), and (2) bought two batteries as I returned the first set thinking it was a "glitch" and I really didn't need them.

    Do key fob batteries go bad at the same time? I'd think I could have gone a while on the second (unused) fob before getting the warning message, but it happened the first time I shut down the Prius on the new fob.

    Does cold weather affect the system? Prius is parked overnight in a garage that doesn't get anywhere near freezing on the inside, and the fob is in my gear bag on the passenger seat. I don't see how the car being cold (on the outside) would trip a false alarm.
     
  2. JC91006

    JC91006 Senior Member

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    You should change them both together, they drain at almost the same rate.

    I changed mine out when battery was low, went to the spare that I rarely use, a few weeks later, same low warning. So they drain even as they sit
     
  3. lefteye219

    lefteye219 Junior Member

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    I would agree with the above advice, I have replaced my Keyfob batteries twice over 6 years and they almost drain at around the same rate.
     
  4. bodgm

    bodgm Junior Member

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    Do you have to get the batteries from Toyota or can you get them at Batteries plus? How much?

    Posted via the PriusChat mobile app.
     
  5. AubreyIII

    AubreyIII Junior Member

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    I bought one last night at Autozone...it was about $8. If I remember right it was a 1632 battery.
     
    bisco likes this.
  6. bisco

    bisco cookie crumbler

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    drug store, big box store, any place that sells button batteries. amazon, whatever. i usually get duracells, a couple bucks each.
     
  7. mmmodem

    mmmodem Senior Taste Tester

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    If the key fob experiences interference, it could give out a false low battery signal like if you put it in contact with metal or have it deep inside a bag. I've read from some member not to leave the fob in close proximity to the car as it uses more battery.

    My first battery gave out in less than a year. The other fob gave out two years after that. So that's 3 years total for the second fob. I'm back to my first fob and it has been fine for over a year in use plus one year sitting. My guess is the dealer has a stack of these fobs and program them to cars as they come in and they don't really care about first in first out rules.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    I'm not sure, but always thought the fobs were assigned to the cars at the factory, and ship with the car, maybe in some specially lined bag to avoid the car constantly detecting it??
     
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  9. jdcollins5

    jdcollins5 Senior Member

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    I have tried key fob batteries at Walmart and Batteries Plus. They were both cheap Chinese units that only lasted about a year.

    I just started getting the Key Not Detected with the fob in my pocket. I checked the battery and it was down to 3.04V. I have found that when it reaches 3.02V it will start triggering the Low Key Battery alarm.

    It appears just removing the battery and reseating it has helped with the Key Not Detected alarm for the time being.

    I have seen on here that the Duracell batteries appear to be the best. I just ordered two from Amazon.
     
  10. AutumnWynn

    AutumnWynn Junior Member

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    Hi Prius friends... could someone please tell me which (if either), of the 2 batteries I need for the fob for my 2006 ....?

    Or...


    Thanks!
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Pop the cover off and see what's in there? The number designation's the same, regardless of brand, I think.
     
  12. Ed Beaty

    Ed Beaty Active Member

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    CR2032 is the 'ticket' for Gen 2 fobs.
     
  13. AutumnWynn

    AutumnWynn Junior Member

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    Thanks!