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Battery Bars Fluctuate - Drop in MPG

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by dmaxdmax, Jan 3, 2013.

  1. dmaxdmax

    dmaxdmax Junior Member

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    I have an '05 with 104,000 miles. Recently I noticed that instead of our usual 49-51 MPG we're seeing 40-42. I switched the MFD to info and saw the electric motor wasn't kicking in except from about 0-2 mph from a dead stop. After that the ICE was doing all of the work. 90%ish of the time the ICE was powering the battery.

    Then I noticed that the battery bars kept moving from the medium low to medium high range every few minutes though not in any pattern that I could discern. This was all in-village driving <30 mph.

    Any thoughts?
     
    #1 dmaxdmax, Jan 3, 2013
  2. SteveLee

    SteveLee Active Member

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    #2 SteveLee, Jan 4, 2013
  3. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    If you find the 12V battery to be in good shape, these are classic signs of a traction battery about ready to go. But let's hold out hope for now and see what the 12V looks like.
     
    #3 usnavystgc, Jan 4, 2013
  4. richard schumacher

    richard schumacher shortbus driver

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    Test the 12V battery first. Definitely do not replace the traction battery without a more specific diagnosis :_>
     
    #4 richard schumacher, Jan 4, 2013
  5. dmaxdmax

    dmaxdmax Junior Member

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    The 12V is 6ish months old.

    If it's ok maybe I should see what Toyota will give me on a trade-in before it starts throwing error codes.
     
    #5 dmaxdmax, Jan 4, 2013
  6. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    Well, as we've found out b4, age has nothing to do with the health of a 12V battery. It would be very prudent to check the voltage on your 12V battery b4 you do anything.
     
    #6 usnavystgc, Jan 4, 2013
  7. dmaxdmax

    dmaxdmax Junior Member

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    Would Autozone check that for me?
     
    #7 dmaxdmax, Jan 4, 2013
  8. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    They would but, why not DIY by following the procedure posted by SteveLee?
     
    #8 usnavystgc, Jan 4, 2013
  9. ahmeow

    ahmeow Prius Lover

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    Where are you living? If in CA, the traction battery is still under warrenty, up to 150,000miles.
     
    #9 ahmeow, Jan 4, 2013
  10. dmaxdmax

    dmaxdmax Junior Member

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    I'm in NC so I think I'm up the proverbial creek.

    I ran SteveLee's procedure and the numbers were fine except when moving to the second step (Power a second time without the brake pedal) the display showed 11.8 for about one half second before jumping back up to 12.2.

    Now what?
     
    #10 dmaxdmax, Jan 4, 2013
  11. SteveLee

    SteveLee Active Member

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    What were the first and last values? We need all 3 values. Writing them down as they come up is a good idea. What part of NC are you located? Had you changed anything at all on the car just prior to the MPG drop? Tires, tire pressure, oil, is the engine running smoothly? Any other observations of variations in the running or operation of the car or how or where it is being driven?
     
    #11 SteveLee, Jan 5, 2013
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