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Thread: U0101 - Lost Communication With The TCM

  1. Top Of Page | #1
    Ron60w's Avatar

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    U0101 - Lost Communication With The TCM

    In case my sig doesn't show I have 2014 Ram 3500 Laramie Mega Aisin with 74k deleted with DRD MM3 for over a year.

    I had just drove 80 miles to drop off my 5th wheel camper to have some items taken care of.

    I unhooked, pulled out of the drive and about 1/4 mile down the road, the traction control light came on, check engine light came on, and had messages 4 wheel drive service temp unavailable, and service electronic braking system.

    The truck jumped around in gears with the selector letters changing between yellow and white.

    I pulled over and shut the truck off for a couple minutes and when I started it, the letters were white but I still had lights on.

    The truck drove fine for 40 miles until I stopped for a bite to eat.

    I pulled the codes and had U0101.

    The truck again drove fine the rest of the way home.

    This morning after doing a bunch of research I found that there are common issues with the wiring behind the drivers front wheel well.

    I pulled out the cover and check all wiring. Seemed fine.

    Started the truck and the gear letters are yellow and I have codes U0101, U0121, and U1412.

    I dropped my MM3 box from under the dash to verify all connections to the TCM.

    Nothing seems obvious.

    Any thoughts?

    Would I create problems by flashing the truck to stock and back?

    Thanks.

    2014 Ram 3500 Mega Cab, Stock Aisin, Toyo RT 35*12.5r20, complete DRD MM3, 4" MBRP TBE 6" Tip, Stock intake, not studded, 63K as of 6/19/19

  2. Top Of Page | #2
    More Powa! RATLIN'HP's Avatar

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    Re: U0101 - Lost Communication With The TCM

    Batteries, battery connections, grounds.

    That's where I'd start and have you cleared the codes with the MM3?

    Sent from my SM-A505U using Tapatalk

    2015 Black Laramie CCSB 3500 SRW. Thuren Leveled With Fox 2.0 Shocks. Ride Rite Rear Air Bags With Wireless Airlift Onboard Air. 35" Toyos. All The Options Minus The Soot Cookers. RaceMe Ultra.

  3. Top Of Page | #3
    Ron60w's Avatar

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    Re: U0101 - Lost Communication With The TCM

    I've tried clear DTC's with the MM3 but the CEL stays on and the codes return on the next key cycle. I've tried disconnecting the batteries for a period of time. Didn't reset. The weird thing is that I never shut the truck off when i unhooked my camper so there should not have been a loss in power. I literally pulled in, unhooked, and pulled away. It was a sunny 95 degrees out. I always monitor my gauges when towing and nothing was out of the norm. I would rather not throw $300 at it just to rule out the batteries. I'll try to start it on a charger to see if that helps. Its too dang out outside to troubleshoot but I need this fixed for a weekend trip...

    2014 Ram 3500 Mega Cab, Stock Aisin, Toyo RT 35*12.5r20, complete DRD MM3, 4" MBRP TBE 6" Tip, Stock intake, not studded, 63K as of 6/19/19

  4. Top Of Page | #4
    More Powa! RATLIN'HP's Avatar

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    Re: U0101 - Lost Communication With The TCM

    Are batteries original?

    Sent from my SM-A505U using Tapatalk

    2015 Black Laramie CCSB 3500 SRW. Thuren Leveled With Fox 2.0 Shocks. Ride Rite Rear Air Bags With Wireless Airlift Onboard Air. 35" Toyos. All The Options Minus The Soot Cookers. RaceMe Ultra.

  5. Top Of Page | #5
    Ron60w's Avatar

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    Re: U0101 - Lost Communication With The TCM

    No. Both batteries were manf 04/18.

    2014 Ram 3500 Mega Cab, Stock Aisin, Toyo RT 35*12.5r20, complete DRD MM3, 4" MBRP TBE 6" Tip, Stock intake, not studded, 63K as of 6/19/19

  6. Top Of Page | #6
    More Powa! RATLIN'HP's Avatar

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    Re: U0101 - Lost Communication With The TCM

    If batteries and battery terminals are good, and grounds are tight, might try cleaning the pin harnesses to TCM, PCM, ECM.

    Sent from my SM-A505U using Tapatalk

    2015 Black Laramie CCSB 3500 SRW. Thuren Leveled With Fox 2.0 Shocks. Ride Rite Rear Air Bags With Wireless Airlift Onboard Air. 35" Toyos. All The Options Minus The Soot Cookers. RaceMe Ultra.

  7. Top Of Page | #7
    Ron60w's Avatar

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    Re: U0101 - Lost Communication With The TCM

    So I might have made some progress but not 100%.

    I did notice that one of the wires on the CAN Bus plugs behind the fender well had pushed out and probably wasn't making a good connection.

    After stuffing the wire in and re-connecting the harness, I was able to start the truck and the gear selectors were white.

    I was able to take it for a drive and truck ran normally.

    However, the CEL is still on and the U0101 Lost Comm with TCM is still present.

    I did not get the 4 wheel drive temp unavailable or the service elec brake system messages this time.

    Probably gonna have to make a trip to a shop. Do you think a scanner will be able to detect or initiate a connection with the TCM?

    That's what I'm hoping for.

    2014 Ram 3500 Mega Cab, Stock Aisin, Toyo RT 35*12.5r20, complete DRD MM3, 4" MBRP TBE 6" Tip, Stock intake, not studded, 63K as of 6/19/19

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  9. Top Of Page | #8
    AA-R's Avatar

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    Re: U0101 - Lost Communication With The TCM

    Quote Originally Posted by Ron60w View Post
    So I might have made some progress but not 100%.

    I did notice that one of the wires on the CAN Bus plugs behind the fender well had pushed out and probably wasn't making a good connection.

    After stuffing the wire in and re-connecting the harness, I was able to start the truck and the gear selectors were white.

    I was able to take it for a drive and truck ran normally.

    However, the CEL is still on and the U0101 Lost Comm with TCM is still present.

    I did not get the 4 wheel drive temp unavailable or the service elec brake system messages this time.

    Probably gonna have to make a trip to a shop. Do you think a scanner will be able to detect or initiate a connection with the TCM?

    That's what I'm hoping for.
    Ron, I have the same RAM (damn) issue!

    2015 Ram 3500 Limited 4x4 Aisin airride 138k mi MM3 tuned by DRD.

    I will check the wiring behind driver fender.

    I heard about that wiring issue awhile ago!



    Sent from my SM-G973U using Tapatalk


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  11. Top Of Page | #9

    Re: U0101 - Lost Communication With The TCM

    Did you ever figure out the problem?

    I am having a similar issue myself.


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  13. Top Of Page | #10
    I WILL STAND! AK Bob's Avatar

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    Re: U0101 - Lost Communication With The TCM

    Quote Originally Posted by Kawi_built View Post
    Did you ever figure out the problem?

    I am having a similar issue myself.
    While you are waiting for a reply, see attached.

    Attached Files Attached Files
    2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit, Cold Air Intake, City Diesel Actuator and 50 Gallon Aux Fuel Tank.

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