Unplugging the 12 V battery

Discussion in 'Gen 3 Prius Technical Discussion' started by Manhal K Alrashdan, Nov 7, 2015.

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  1. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    Some one had advised me that when buying a used prius, I should unplug the positive cable of the 12v battery for about ten minutes so to reset the car memory of the previous owner's driving habits. According to this "expert "this will improve the car's Mpg.
    Is there any truth in this assumption?
     
    #1 Manhal K Alrashdan, Nov 7, 2015
  2. bisco

    bisco cookie crumbler

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    nope.
     
    #2 bisco, Nov 7, 2015
    Last edited: Dec 26, 2015
  3. vskid3

    vskid3 Active Member

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    Also, when removing battery cables, it's best to remove the negative first. If you accidentally hit your tool to bare metal while on the negative, nothing happens. Do that while on the positive with the negative still attached and you'll have quite the light show.
     
    #3 vskid3, Nov 7, 2015
  4. David Beale

    David Beale Senior Member

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    The car will quickly learn your habits, if different than the previous owner. If you disconnect the 12V you may loose some setting you might want, such as reverse beeping "one beep" to "continuous". There is also a slight possibility you may "zap" the electronics if you do it wrong.

    Best to just drive it.
     
    #4 David Beale, Nov 7, 2015
  5. StarCaller

    StarCaller Senior Member

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    shouldn't things like that be permanently stored?
    as far as I remember, when I switched my 12v battery there was none of those settings gone/
    (& no, I'm not going to disconnect my battery now just to see what happens.... ;) :) )
     
    #5 StarCaller, Nov 7, 2015
  6. Andyprius1

    Andyprius1 Senior Member

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    I have done this several times, it doesn't hurt anything. You will have to reset time and date. It will increase your EV range slightly, say from 12 to 13 maybe. Also if you are having screen problems it will reset various computers and take care of these problems. Yes, it's safer to remove the NEG.
     
    #6 Andyprius1, Dec 26, 2015
  7. Lucifer

    Lucifer Senior Member

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    As its a digital device a cold reboot periodically is a good idea, and if the prior owner was very light footed, remapping the computers to full ahead takeoffs will add mpg's, the faster you get to cruising speed the better.
     
    #7 Lucifer, Dec 26, 2015
  8. fuzzy1

    fuzzy1 Senior Member

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    No that I've heard in more than six years on this forum.
    OP does not have a Plug-In version, so this does not apply.

    Even on the Plug-In, I'd think it would reset only the 'historic' mpg figure to the factory default, used to estimate range. The car's actual range should not be changed.
     
    #8 fuzzy1, Dec 26, 2015
  9. bisco

    bisco cookie crumbler

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    i've never understood the 'drivers habits' thing. when i press on the go pedal, it goes. same with the brake. what else is there?
     
    #9 bisco, Dec 26, 2015
  10. Andyprius1

    Andyprius1 Senior Member

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    I have had a Gen 2 and now the PIP and have rebooted both cars several times. No harm and slightly extended range.
     
    #10 Andyprius1, Dec 26, 2015
  11. Andyprius1

    Andyprius1 Senior Member

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    Me neither , something from coast to coast maybe.
     
    #11 Andyprius1, Dec 26, 2015
  12. bisco

    bisco cookie crumbler

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    that's probably it. what if two people drive the car, will it need treatment for bipolar disorder?:cool:
     
    #12 bisco, Dec 26, 2015
  13. UberXking

    UberXking Junior Member

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    Probably the seller recommended this. Disconnecting the battery will remove the check engine light for a few miles.
     
    #13 UberXking, Dec 29, 2015
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    Between me 'n the wife, would our car be conflicted? o_O
     
    #14 Mendel Leisk, Dec 29, 2015
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