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I think my 12v finally went

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ryanpl, Oct 25, 2010.

  1. Ryanpl

    Ryanpl Active Member

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    hi fellow PCers, I believe the battery on our 2004 Prius is on the way out the door and fast. We lent Mina to a friend on Saturday and the following day we got a MPG display of 17.1, while dirving we jumped back to 45ish MPG. While thae low MPG is weird it's only the beginning. The break light indicator came on and remained on and the ABS, VCS and (!) lights all remained on in yellow. I checked the voltage via the secret squirrel menu and had 11.6v in acc mode and it jumped to 13.3 volts wile driving. Is there a way to clear the error lights while waiting for the battery? The car breaks and handles normally so I do not think the lights are just 12v warnings. If needed I'm going to order the Optima replacement this Friday. In the mean time is there a way to clear the lights? I do not have any special code readers only the MDF and maybe a helpful person within NYC that can clear the codes. We got the car used from a dealer so I am unable to tell when and if the original owner ever changed the 12 v.
     
    #1 Ryanpl, Oct 25, 2010
  2. firepa63

    firepa63 Former Prius Owner

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    If I were you I would start carrying a spare 12v battery. You'll be lucky if a new Optima arrives before you can't start your car. There's no need to clear the error lights because if you have low 12v bus voltage, the lights are just going to come back on.
     
    #2 firepa63, Oct 25, 2010
  3. andyprius

    andyprius Senior Member

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    Try running the car in Ready mode (driving mode) let charge for several hours, then look at 12V Soc. After 12V is totally charged up (12.3 to 12.5 Volts) for a older battery, then reboot. OR: Wait til you get the new 12V Bat and the act of disconnecting the battery will be a REBOOT. This should remove the warnings. Study archived threads.
     
    #3 andyprius, Oct 27, 2010
  4. partsmore

    partsmore Junior Member

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    I have a new 12V Toyota battery out of my 2010 -
    if you're interested.
     
    #4 partsmore, Oct 27, 2010
  5. Ryanpl

    Ryanpl Active Member

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    After charging for a several hours best I was able to get was 12.1. New battery is on order. Thanks Andy for your help I'm going to wait for new battery and just reboot.
     
    #5 Ryanpl, Oct 27, 2010
  6. andyprius

    andyprius Senior Member

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    #6 andyprius, Oct 27, 2010
  7. andyprius

    andyprius Senior Member

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    Where are you located, and would you be interested in mailing the battery COD to me, to include postage???
     
    #7 andyprius, Oct 27, 2010
  8. Ryanpl

    Ryanpl Active Member

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    ok I changed my battery today to a yellow top and still have warning lights. How do I reset the lights??
     
    #8 Ryanpl, Nov 11, 2010
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you had totally removed 12V power to the system while in the process of replacing the 12V battery, then most DTC should have cleared. Assuming that you had removed 12V power, then if you still see warning lights you likely have a real problem and should visit your local Toyota dealer so that the DTC can be read and a diagnosis provided to you.

    Alternatively (at your risk) you can do a search for my posts on how to clear skid control ECU DTC. I say that performing that process is at your risk because if your car has a real problem, your clearing the DTC will delay the diagnosis and resolution of the problem. Good luck.
     
    #9 Patrick Wong, Nov 11, 2010
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