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New 12v battery installed...now master key won't function

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by databell, Jun 2, 2011.

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  1. databell

    databell New Member

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    I just had my mechanic put in a new 12 volt battery in my 2005 Prius. Car runs fine now but the master key no longer locks and/or unlocks the car. I also can't start it unless I insert the master key directly into its' near the ignition. I've also had issues where the alarm will go off for no apparent reason. Something must gave transpired when the car got reset. Is there a fix for this without hsving to go to Toyota to get the key reprogrammed?
     
    #1 databell, Jun 2, 2011
  2. cwerdna

    cwerdna Senior Member

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    Have you replaced the batteries in the key fobs?

    I know he's changed the 12 volt, but have you checked its voltage? Try http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html after the car has sat for many hours or overnight.
     
    #2 cwerdna, Jun 2, 2011
  3. stefano5777

    stefano5777 Member

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    There is a switch under the steering column for SKS key check to make sure that was not switched off by accident.
     
    #3 stefano5777, Jun 2, 2011
  4. databell

    databell New Member

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    I found the switch and pushed it out. Now the keyless startup works. However, I still can't lock and/or unlock the door with the master key. Guess that's the battery dying?
     
    #4 databell, Jun 2, 2011
  5. stefano5777

    stefano5777 Member

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    Most likely that is due to a dying Battery in fob. And your welcome :)
     
    #5 stefano5777, Jun 2, 2011
  6. cwerdna

    cwerdna Senior Member

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    Why don't you change the key fob batteries if they've never been changed? CR2032 batteries (each fob takes one) can be had for <$2, if you go to the right places.

    I had to replace the key fob batteries for my 06 Prius in the past year or so. The car was bought new.
     
    #6 cwerdna, Jun 2, 2011
  7. databell

    databell New Member

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    I was wondering about that. Where can you get those batteries? Target? Wal-Mart? AutoZone? Thanks.
     
    #7 databell, Jun 2, 2011
  8. cwerdna

    cwerdna Senior Member

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    FRYS.com has them but I think all are too far for you to make it worthwhile. They are definitely <$2 there.

    All of the ones you listed should have them. Radio Shack has them at a ripoff price. Many drugstores and supermarkets have them but usually at not great prices. The Big 5 Sporting Goods up here had them at a not so horrible price (they had Duracell DL2032 which are equivalent to CR2032).

    I posted about pricing at http://priuschat.com/forums/gen-ii-...-beam-both-fobs-quit-working.html#post1295408 and there's another source further down for cheaper batteries.
     
    #8 cwerdna, Jun 2, 2011
  9. databell

    databell New Member

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    I just placed a new battery into my Smart Key but nothing changed. Just to recap, I can do everything I did previously prior to the new 12v being installed except I cannot use the fob to lock and unlock the door, although the trunk does open on sensor, and the theft deterrent system goes off on occasion.
     
    #9 databell, Jun 3, 2011
  10. cwerdna

    cwerdna Senior Member

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    #10 cwerdna, Jun 3, 2011
  11. databell

    databell New Member

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    I tested that and everything checked out OK. So it's not the new battery. So what could it be?
     
    #11 databell, Jun 4, 2011
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    Just my guess: something about the key fob is held in the car's memory, and with the 12 volt battery replacment that memory was lost, needs to be re-initialized?

    Did you lose your radio presets? If so that would confirm the mechanic did not supply voltage when swapping batteries.
     
    #12 Mendel Leisk, Jun 4, 2011
  13. efusco

    efusco Moderator Emeritus
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    Open and close all the doors tightly and try again. I can't think of anything that would cause you to be able to use the sks to start the car but not open any of the doors with the sks.

    Just to clarify, can you lock/unlock the hatch with the smart key, but NOT the driver and passenger door?? Or is the hatch involved too? Have you tried both the driver's side and passenger side doors' sensors?

    It is possible that something happened to the driver's side door oscillator (the key sensor) and it may need to be replaced.

    Finally, if this happened when the battery was changed by the dealer I'd drive directly there and insist that they fix what they broke.
     
    #13 efusco, Jun 4, 2011
  14. databell

    databell New Member

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    Yes, Mendel, in fact I did lose my radio presets.
     
    #14 databell, Jun 4, 2011
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Try the other fob, after installing a new CR2032 battery in it. If neither fob works then you'll need to seek Toyota dealer assistance.
     
    #15 Patrick Wong, Jun 4, 2011
  16. databell

    databell New Member

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    Unfortunately, I lost my other FOB a long time ago when I was living in New Orleans and Katrina hit. Never packed the spare.
     
    #16 databell, Jun 4, 2011
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Another reason to visit your dealer. Unfortunately a new fob will probably cost ~$300.

    If you lose your last fob then you'll face a much larger repair bill as the dealer tech will have to reinitialize the immobilizer ECU before new fobs can be added.
     
    #17 Patrick Wong, Jun 4, 2011
  18. databell

    databell New Member

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    Quick Update. I finally took the Prius to my local Toyota dealer. Turns out the battery was dead. And itKs a new battery! Why? Seems the panic button on the keyfob was jammed in and they corrected it and placed in a new battery. Total cost? Four bucks. That's right. No labor expenses. How rare is that for a dealer NOT to charge? They did say if the button gets jammed again, I will need to bite the bullet and purchase a new FOB. So I'm hoping that's not going to happen anytime soon. Thanks to all for their suggestions and help.
     
    #18 databell, Jun 15, 2011
  19. Hal W

    Hal W New Member

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    Use the pads on the door hdl. rather than the FOB buttons. Hal
     
    #19 Hal W, Jun 15, 2011
  20. Eug

    Eug Swollen Member

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    You can get CR2032 batteries off eBay for $3, for a multipack. I order some in advance and then just replace the batteries in my two FOBs every so often whether I need it or not.

    Actually, IIRC you're supposed to replace them every year, but it seems fine in my case to replace them every 2 years.

    How long do your FOBs' batteries last?
     
    #20 Eug, Jun 15, 2011
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