Smart key with a new battery not working

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mira4581, Aug 31, 2012.

  1. mira4581

    mira4581 Junior Member

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    Hey guys, I have a 2007 Prius 2, the key will not open the doors, so I went to the store replaced the remote battery but it is still not working. The light on the remote lights up as usual. I can get in using the small metal key, the car starts and everything seem to be working fine with the smart key plugged in. The 12v battery seems to be fine as all the lights work when the car is off. Any idea what this might be? Thanks for the help.
     
    #1 mira4581, Aug 31, 2012
  2. mira4581

    mira4581 Junior Member

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    I figured it out. I had to disconnect my 12v battery and it started working.
     
    #2 mira4581, Aug 31, 2012
  3. cwerdna

    cwerdna Senior Member

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    #3 cwerdna, Aug 31, 2012
  4. mira4581

    mira4581 Junior Member

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    I checked it this morning on both of my Prius's. The problem one showed: 1 step: 11.9, 2 step: 11.6, 3 step: 14.1 and my other car 2007 Prius 5 showed 1 step: 12.0, 2 step: 11.7, 3 step: 14.1. Both batteries are original and based on the numbers do you think I might need to change them both? I don't really notice a mpg drop I can get 50 mpg if I want but usually get about 45 mpg on average on both of them.
     
    #4 mira4581, Sep 1, 2012
  5. Salvage09

    Salvage09 Junior Member

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    #5 Salvage09, Sep 1, 2012
  6. Salvage09

    Salvage09 Junior Member

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    You need a new 12 V battery. All sorts of weird stuff happens when the 12V battery gets low-it's like the car computer is drunk. Probably why the keys stopped working. Optima has a better-than-original replacement; comes with detailed instructions to replace yourself. Only thing I would add to their instructions is either use magnetized sockets, or cellophane/invisible tape to hold the nuts/bolts in the sockets when you're reassembling. I dropped the grounding strap bolt, it rolled under the battery, and I had to remove the battery to recover the bolt. So if you're a butterfingers like me, secure the nut/ground bolt in the socket so it can't drop out.
    But definitely replace the 12 V battery.
     
    #6 Salvage09, Sep 3, 2012
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