2009 Prius MFD intermittently working

Discussion in 'Gen 2 Prius Audio and Electronics' started by TSegal, Nov 10, 2022.

  1. TSegal

    TSegal New Member

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    Location:
    Rio Grande, New Jersey
    Vehicle:
    2009 Prius
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    N/A
    Hi Everyone, we have a 2009 Prius with about 140,000 miles on it. We had to replace a belt and the garage said our 12volt battery was testing low and we should replace it which we did with an optima battery. A few months later our MFD went black then came back on when we touched any of the buttons or turned off the car and restarted it. the car would go for days and the MFD worked fine. During this time the info and climate buttons worked but the display was dark. Now the display doesn't always work until you are driving for a bit and then the display will come on but not work if you touched it then fade to white. Then the next day the display comes on a works just fine with both buttons and touch. Also when MFD comes back on its reset to original color etc... other times it keeps its settings. We did look at the diagnostic and it does not have any errors and says that the 12v battery is ok. Any Thoughts?
     
    #1 TSegal, Nov 10, 2022
    Last edited: Nov 10, 2022
  2. Tombukt2

    Tombukt2 Senior Member

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    Usually the display is going bad . I just get replacements from other cars.
     
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  3. FiveToes

    FiveToes New Member

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    Location:
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    Vehicle:
    2006 Prius
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    I had an odd experience that was a little different than yours. It may or may not be helpful. Probably 2.5 years ago my MFD wouldn't come on when I'd start the car. It would take 2-5 mins of me driving for it to come on. I'd be listening to a podcast and get the tell tale 1 second drop in sound from the speakers as the MFD booted. After a while it just stopped turning on at any point on some drives. For the better part of the last year it might turn on mid-drive once a month. I looked up replacements and they were in the $1k-$2k range and put it off. About a month ago I found the Dr Prius app. I'd been using Torque pro without the extra Prius PIDs for years and ran across Dr Prius somewhere. When I was driving, most of the time I'd keep off the brakes. I figured the coasting did better regeneration than the brakes so I'd coast up to stop lights as long as I wasn't backing up traffic, only applying the brakes at the very end. I hadn't seen the SOC screen on my MFD for a long while since the screen stopped working. Watching the amps going into the battery and the SOC % showed me how wrong I was. Coasting netted me 17-20 amps and refilled the SOC % very slowly. Light to moderate braking over reasonable distance netted me 50-85 amps and really added to the SOC %. Dr Prius said I was initially in the high 40% SOC when I first connected it. I live in the Appalachian mountains so I took a quick drive over the mountain and back a few times, figured out how great braking worked refilling the SOC, and got it up to 77% SOC. Since then the MFD has come on every time I've started the car. I was absolutely baffled but apparently appropriate battery voltage is required to get something in it to work correctly.
     
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  4. TSegal

    TSegal New Member

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    Location:
    Rio Grande, New Jersey
    Vehicle:
    2009 Prius
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    We were hoping that it might be something else like a short or a bad connection with the 12volt battery. not an easy replacement and we can't afford to have Toyota repair it.
     
  5. TSegal

    TSegal New Member

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    Location:
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    Vehicle:
    2009 Prius
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    N/A
    Thank you for that information. I wouldn't have known about the braking and mfd. We had our battery replaced and really think it has something to do with that however the battery tests at 12.4 volts. We didn't have ANY issue with the mfd until we replaced the battery. Now we are trying to manage the car with only using the steering wheel controls until we get it repaired. Thank you for taking the time to respond.
     
  6. Tombukt2

    Tombukt2 Senior Member

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    The Toyota dealer won't repair it they'll replace it and it'll be about a thousand plus dollars if they even have it and their inventory 09 you're at the last of the series.
     
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