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  1. #1
    Gold Member
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    Oct 2003
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    Northern California
    Tractor
    New Holland TN70S

    Default Power Shuttle failure - code 78? What\'s that?

    Does anyone have their TN series service manual handy? I was out doing some work in deep mud/muck yesterday, and all of sudden the tractor decided it wasn't going anywhere. The Power Shuttle failure indicator showed a code 78, and the transmission disabled warning light stayed on - and we just weren't going anywhere anytime soon. I'm thinking that I was so deep in the muck that something got wet - and that's what I'm hoping happened. I checked all fluid levels, and looked around to see if I tore any wires loose, and everything looks fine.

    After cycling through a few shut-downs and start-ups, the transmission controller reset itself and I was able to drive to dry land - but I sure would like to know what possibly went awry. Thanks in advance to anyone who has that code and any ideas handy!


  2. #2
    Gold Member
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    Oct 2003
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    465
    Location
    Northern California
    Tractor
    New Holland TN70S

    Default Re: Power Shuttle failure - code 78? What\'s that?

    One possible clue: I was under the tractor poking around, and I found a disconnected two-pronged plug hanging loose. I can't for the life of me figure out what it used to plug into - so I don't know if it's related to the Power Shuttle failure or not. It's located on the left side of the transmission (when looking at the tractor from the rear) very close to the fuel tank inlet.

    The failure is very strange - I can run the tractor for about ten minutes, and then all of a sudden the failure warning light will come on and the transmission will get disabled. I can shut down the tractor, re-start it, and everything's fine for another ten minutes or so.

  3. #3
    Veteran Member 1bush2hog's Avatar
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    Jul 2003
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    1,088
    Location
    Georgia
    Tractor
    NH TN75

    Default Re: Power Shuttle failure - code 78? What\'s that?

    POWER SHUTTLE CONTROL SYSTEM ERROR CODE

    78 - Desc. - Power supply tension - low
    Cause - ECU module faulty

    Hope this helps.


  4. #4
    Gold Member
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    Oct 2003
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    465
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    Northern California
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    New Holland TN70S

    Default Re: Power Shuttle failure - code 78? What\'s that?

    Thanks!! That helps a lot!

  5. #5
    Veteran Member 1bush2hog's Avatar
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    Georgia
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    NH TN75

    Default Re: Power Shuttle failure - code 78? What\'s that?

    I have the repair manuals. If you need for me to scan/email you any additional info just PM me.

    Good Luck.

    My TN75 is down with error code 41, meaning a new forward synchro is needed for the PS. Think I'll let the dealer tackle it, but the problem is my tractor is about 1.5 mi off the main road (that's why I got MFWD) and he wants to send a truck to haul it in.

    It's too wet for me to do anything right now anyway with the TN, but still I am surprised this problem occured with mione having only 70 hours on it.


  6. #6
    Gold Member
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    Oct 2003
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    465
    Location
    Northern California
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    New Holland TN70S

    Default Re: Power Shuttle failure - code 78? What\'s that?

    Thanks - I apreciate that! The dealer seems to think that my error code is a result of something wrong with the seat sensor. I'm going to dig around and see if anything under there came loose.

    Good luck with yours - it's a real pain to not have these tractors running when you need them.

  7. #7
    Veteran Member 1bush2hog's Avatar
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    Location
    Georgia
    Tractor
    NH TN75

    Default Re: Power Shuttle failure - code 78? What\'s that?

    I believe the sensor connector for this is under the seat frame above the rear axle - right side. You may want to check this connector on yours. The dealer left this one loose on mine one time after service.

  8. #8
    Super Member RickB's Avatar
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    Sep 2000
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    7,986
    Location
    Eastern NY
    Tractor
    Case 885, Ford 4000

    Default Re: Power Shuttle failure - code 78? What\'s that?

    I don't think a seat switch or circuit failure will disable the transmission. Have seen cut wires and failed switches, and the beeper will drive you nuts, you can't shuttle without clutching, but it isn't disabled. Just got home from the Cup race in Darlington and don't have the codes at home. Willl try to remember to check tomorrow.

  9. #9
    Super Member RickB's Avatar
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    Location
    Eastern NY
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    Case 885, Ford 4000

    Default Re: Power Shuttle failure - code 78? What\'s that?

    TN's have extra unused connectors in that area. I think the harness is common with the TNF which has a High/Low as well as F/R in the PowerShuttle system. From memory, I think 78 indicates a ECM failure. Have seen this on two TL and one TN tractor, all built about 12-15 months ago. All crapped out at VERY low hours. No other ECM failures on at least 25 other PowerShuttle tractors. Will try to have more info tomorrow.

  10. #10

    Join Date
    Mar 2001
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    1,211
    Location
    Northern Virginia
    Tractor
    2001 New Holland TC40D w/16LA loader

    Default Re: Power Shuttle failure - code 78? What\'s that?


    </font><font color="blue" class="small">( Just got home from the Cup race in Darlington )</font>

    Good race! Who did you root for?

    Mark

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