MFD Blank and Unresponsive, Replaced 12v battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by priuszzz, Sep 12, 2014.

  1. priuszzz

    priuszzz New Member

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    I have a 2008 Prius, MFD died one day, screen completely dark and all buttons on it are unresponsive. I used a voltmeter to check the 12v battery which had troubles last winter (had to jump it once) and it was at about 10.6v so I just replaced it with an Optima battery. Sadly the MFD is still blank.

    The MFD actually came on for a second a couple weeks ago which led me to believe it was still functional and just not getting enough power from a failing 12v.

    Does it take a while for a brand new battery to fully recharge and could that fix the problem or is something worse going on? Could it also be a blown fuse somewhere? I'll feel very dumb if I got a new battery for nothing but it needed to be replaced anyway I think.

    If it is a fuse, is there a simple guide I can follow to find the bad one? What I've read so far is pretty confusing regarding the fuses.

    I also noticed in the Common 2G Problems thread there is a mention of a strange noise on startup that can be fixed if the car is under powertrain warranty. I do hear a strange noise sometimes like a sucking squealing when I turn on the AC, is this the same thing?
     
    #1 priuszzz, Sep 12, 2014
  2. Easy Rider 2

    Easy Rider 2 Senior Member

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    No not really.
    But it appears that you HAVE a voltmeter.
    Use it.
    It is possible that your charging system (inverter) is failing.

    Your display problem likely is a bad connection, either inside the display itself or the wires feeding it.
     
    #2 Easy Rider 2, Sep 12, 2014
  3. JC91006

    JC91006 Senior Member

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    What's the reading on the new 12v you installed?

    The noise you are referring to at start up and shut down is the pump that fills coolant to the thermos. I don't think it's an AC related noise. If that pump is making noises, there was an extended warranty for that pump but not sure if that's still valid in your case.
     
    #3 JC91006, Sep 12, 2014
  4. priuszzz

    priuszzz New Member

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    I haven't checked it yet, just installed it today. I'll check it and see if it's where it should be. Should I run it for a little bit to fully charge the 12v or should it be okay to check as it is? I only drove it about 5-10 minutes after it was installed.
     
    #4 priuszzz, Sep 12, 2014
  5. JC91006

    JC91006 Senior Member

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    The new battery should be no lower than 12.5 volts, if it is, it might give you problems down the road. A fully charged battery is 12.9 volts.

    There have been many people complain about the initial charge on the new Optima batteries. Some are installing batteries that come under 11 volts when new. That's almost a guaranteed disaster waiting to happen.

    I don't think that will fix your MFD but strangely enough there was a member that complained about the MFD and a new battery fixed his problem.
     
    #5 JC91006, Sep 12, 2014
  6. jdenenberg

    jdenenberg EE Professor

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    #6 jdenenberg, Sep 12, 2014
  7. priuszzz

    priuszzz New Member

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    This is weird, I tried to check the battery using the jumpstart point under the hood and I'm not getting anything at all. Am I doing something wrong? I tried the voltmeter on another battery and the voltmeter is working. I put the red probe on the positive jump terminal (looks like a screw thread sticking out) and the negative on the flat terminal above it. Getting 0.0v.

    The car starts and the lights all go on.
     
    #7 priuszzz, Sep 12, 2014
  8. JC91006

    JC91006 Senior Member

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    The negative should go on an unpainted part of the engine or body of the car
     
    #8 JC91006, Sep 12, 2014
  9. priuszzz

    priuszzz New Member

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    Finally got it working, I'm getting 12.38v. Is that acceptable? Just got it shipped here and only drove 5 minutes after install. Just for fun, checked my old battery and it's 10.77v.

    Should I start checking fuses and do you have a guide or link on which fuses to check?
     
    #9 priuszzz, Sep 12, 2014
  10. JC91006

    JC91006 Senior Member

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    It's below the threshold of 12.5 volts as a minimum. But it's pretty close at 12.38v. If you get a chance, charge it up to 12.9 volts. Keep the receipt, you might need the warranty later if it becomes a problem.
     
    #10 JC91006, Sep 12, 2014
  11. Mendel Leisk

    Mendel Leisk MMX GEN III

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    And positive on the flat copper post ( with red flip up cap), in the fuse box.

    Ok, you got it.
     
    #11 Mendel Leisk, Sep 12, 2014
  12. priuszzz

    priuszzz New Member

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    I'll drive it around a bit and see if it just needs a little more charging. I'm still holding out hope that the MFD is still working and just needs more power to start.
     
    #12 priuszzz, Sep 12, 2014
  13. JC91006

    JC91006 Senior Member

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    I believe you need a replacement MFD. The battery has sufficient power and shouldn't be the cause of the MFD not working. Out here in CA, I've seen them for about $100 used.
     
    #13 JC91006, Sep 12, 2014
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