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Air Conditioner Error on MFD

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jaster, Oct 30, 2024.

  1. jaster

    jaster Junior Member

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    I've read through several threads about this problem and not sure what to do next. I started getting this error on the MFD a month ago for the first time in my 2007 Prius: "Check the connection to the air conditioner."
    Here are the variables in my case:
    1. I'm able to control the air conditioner with the steering wheel controls when getting this error, so the air conditioner itself is working.
    2. The issue on the MFD seems like it happens on colder mornings here in Michigan and so far has always cleared up within 10-15 minutes of driving.
    3. I replaced the 12V battery since it was near time to do that anyway. Unfortunately, that didn't solve this issue. I'm still getting the error.
    Is there anything else to check? Is this likely a bad MFD at this point? If so, what happens if I don't replace/fix the MFD? Will it get worse in some way?
     
    #1 jaster, Oct 30, 2024
  2. pasadena_commut

    pasadena_commut Senior Member

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    Did you ever work on the MFD or anything near it in the dash?

    If you put the car (cold) into IG-ON does the diagnostic screen look like the one here:



    with NCON on the last 3 rows?

    When it starts working again, does IG-ON diagnostic screen no longer show the NCONs?

    Since it comes and goes I'm thinking it is one of these: loose and/or dirty/corroded connector at MFD, cracked solder joint in MFD, broken wire in cable, or aging components (especially capacitors) in MFD. The first is the only one that is relatively easy to address. Take the dash apart enough to get the MFD out and inspect and clean all the connectors (both sides). I would use electrical contact cleaner from a spray can, but that might be hard to do for the ones attached to the car. For the MFD it could be sprayed off in the driveway. You do not want to breathe that stuff and the spray might dissolve some plastics in the car if there was direct contact.

    See also:

    Prius 2nd Gen - Repairing the Multi-function Display
     
    #2 pasadena_commut, Oct 30, 2024
  3. jaster

    jaster Junior Member

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    Question. How does one bring up that diagnostic screen, revealing the NCON messages? I've never seen that. When this issue happens, I can press buttons for Audio, Info, and Display and those screens come up fine. Only the Climate screen has the error that says it can't connect to the air conditioner.

    Also, I did replace the Audio unit awhile ago with a Sony unit. The install was does at Best Buy and I haven't had any issues since that work was done. But I suppose in answer to your question, there was work done next to the MFD.
     
    #3 jaster, Oct 31, 2024
  4. pasadena_commut

    pasadena_commut Senior Member

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    #4 pasadena_commut, Oct 31, 2024
  5. dolj

    dolj Senior Member

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    That last instruction should be, "Turn sidelights on and off three times."

    Although it still works, there is no need to turn on the headlights, especially if you have HIDs.
     
    #5 dolj, Oct 31, 2024
  6. jaster

    jaster Junior Member

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    Thanks. Attached is what I get when I'm getting the connection error trying to bring up the A/C.
    EMV: OK
    Audio: NCON
    G/W: NCON

    The Audio NCON status is always on because I swapped out the audio unit with a Sony and I guess that's how that is.
    However, the G/W NCON only shows up when I'm getting the error connecting to the A/C unit.
    During that condition, the Climate button does indeed work but the climate controls don't show up on the MFD.

    Suggestions?
     

    Attached Files:

    #6 jaster, Nov 8, 2024
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