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MFD possible problem 05 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Sarah Bernheim, May 19, 2015.

  1. Sarah Bernheim

    Sarah Bernheim New Member

    Joined:
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    Location:
    NW Michigan
    Vehicle:
    2005 Prius
    Model:
    Four
    We have an 05 Prius very dependable especially given its age, and just over 90,000 miles. Earlier this year I noticed a problem in the AC/Heating system, like gremlins managing the choices. The choices change on whim of whatever and some times just before the heat turns off and turns to blowing cold air, you hear three fast bleeps. An excellent service person said it might be reprogramable by a Toyota dealership but if the MFD itself needs replacing, we might want to live with it, given the cost. Nothing else seems to be affected, just cold air when you are expecting heat or the change back and forth Has anyone experienced this and how did you address the problem?
     
    #1 Sarah Bernheim, May 19, 2015
  2. bisco

    bisco cookie crumbler

    Joined:
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    how is your 12 volt battery health?
     
    #2 bisco, May 19, 2015
  3. hill

    hill High Fiber Member

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    many of the mfd's on the 04's & 05's were plagued with cold solder issues & were taken care of under a TSB. I'd find out if yours was ever changed out if I were you.
    .
     
    #3 hill, May 19, 2015
    Last edited: May 20, 2015
  4. Sarah Bernheim

    Sarah Bernheim New Member

    Joined:
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    Location:
    NW Michigan
    Vehicle:
    2005 Prius
    Model:
    Four
    We had a dead battery twice (late fall/then winter) but a local mechanic said after charging at his place everything looked fine. we had the battery replaced about five years ago. A new battery has to be cheaper than an MFD replacement so it is worth considering. (best source?)Would it take ten years for a cold solder problem to show up?
     
    #4 Sarah Bernheim, May 20, 2015
  5. hill

    hill High Fiber Member

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    Oh it varies ... it could be quick, or a while. Btw, the mfd's that got changed out were rebuilds ... so the costs weren't near as bad as the new ones. The units are modular ... & quite easy to remove. If Toyota no longer takes responsibility for the mfd, one can easily replace them all by their self. I installed an aftermarket speed sensor over ride (called lock pic) on the back of the mfd, which allows you to input map & phone numbers while in motion. I was surprised how easy it was to do. If I recall, their are YouTube vid's showing the procedure.
    EDIT;



    Found it! Yea - my memory still works. A gal up in the bay area has a shop, and she can replace 'em in just 6 minutes! Took me an hour or so, as I'm a slow poke. Other vid's can walk folks through it - step by step.
    .
     
    #5 hill, May 20, 2015
    Last edited: May 20, 2015
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