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2007 Prius 56,000 miles, master brake warning light on and off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ls40095, Mar 10, 2013.

  1. ls40095

    ls40095 Junior Member

    Joined:
    Jan 24, 2013
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    Vehicle:
    2007 Prius
    Model:
    N/A
    Purchased the car several months ago and have done all maintenance and the car is overall flawless but I believe it to contain the original 12V battery.

    3 days ago the brake master warning light came on the dash. No other lights have come on. My scan gauge shows ready and no codes. I checked the reservoir level and seeing that it may have been a tiny bit low, I added fluid and drove the car. Over the last 2 days and about 30 miles the light has come on and off. After adding the brake fluid and taking a few hard bends, the light as I though and issue was gone for good. I even jumped into Maintenance mode. The 12V battery was hovering at 12.1V with the car off. With a load on the battery dropped it down to 11.6-11.8V. The battery level jumped to 14.1V with the car running. I have another 2007 with 100k that I ran in maintenance mode that scored even lower voltage so I figured since I had no battery issues with either car up to this point then the problem with my other Prius have been the reservoir level or sensor.

    Well,
    ​
    The car sat yesterday and this afternoon (its 60 degrees here) the car is completely dead. My jumper box is very low but I gave it a try and still no start or power but when my wife gets home with the other car, I will try to jump start it.....

    Any thoughts? Or is it a no brainer battery?
     
    #1 ls40095, Mar 10, 2013
  2. boppo

    boppo Active Member

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    Location:
    Owego, NY
    Vehicle:
    2006 Prius
    Model:
    II
    I would say go buy 2 new batteries and maybe you can get a better deal. 6 years on that type battery you could say you got your monies worth.
     
    #2 boppo, Mar 10, 2013
  3. SteveLee

    SteveLee Active Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    I
    It does seem like some Prius' can manage on lower battery readings than others. The one that's dead, there should be (no) question. The one that's not, just a matter of time and place. I agree new batteries is the direction to go. You might want to consider BritPrius' observations and recommendation on replacements. Fitting mobility 12volt AGM battery. | PriusChat
    (edit)
     
    #3 SteveLee, Mar 10, 2013
  4. ls40095

    ls40095 Junior Member

    Joined:
    Jan 24, 2013
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    Vehicle:
    2007 Prius
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    I totally agree, but you also think its a slam dunk 12V replacement issue?
     
    #4 ls40095, Mar 10, 2013
  5. ls40095

    ls40095 Junior Member

    Joined:
    Jan 24, 2013
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    Vehicle:
    2007 Prius
    Model:
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    Thank You
     
    #5 ls40095, Mar 10, 2013
  6. boppo

    boppo Active Member

    Joined:
    Mar 11, 2009
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    Location:
    Owego, NY
    Vehicle:
    2006 Prius
    Model:
    II
    If you put the batteries in yourself it would be a lot cheaper than the dealer and since they are 6 years old that will eliminate the battery as your problem.
     
    #6 boppo, Mar 10, 2013
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