CODE U0101 2006-2015 Chevy GMC Duramax w/ 6 Speed Allison Trans: TCM Failure Connector Pinout

DO NOT USE BIG TEST LEADS TO READ ON THIS CONNECTOR!! YOU WILL DAMAGE FEMALE PINS!!
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In this video I show you how i troubleshot my 2007 GMC 2500 Classic that is exhibiting the U0101 transmission control module communication code. This is a very common failure on these 6 speed trucks.
I bought my preprogrammed TCM from: Ryans Diesel Service Let them know you heard about them from here!!!
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Due to factors beyond the control of Mad Mikes Garage, i cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Mad Mikes Garage assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Mad Mikes Garage recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of Mad Mikes Garage, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.

[@brandonhowles]

Hey i was trying to follow along with testing the harness. It seems like my connector is upside down from yours. If my wires from the harness is on the bottom on the connector, my #1 pin is on the bottom right column. But once i figured that out all the test came out good. I have a 2011 sierra 2500 duramax. Maybe they changed it around through the years. Anyway thanks for the video looks like i need a tcm.

[@brandonhowles]

Hopefully this will help someone else

[@madmikesgarage4861]

Thanks for sharing! I pinned this comment for others to see

[@madmikesgarage4861]

DO NOT use a big test light like I did in your connector pins. Doing that hogged out my connector pins and one of the pins was not making contact with my brand new TCM. This caused me to have a persistent CODE U0101 and it also had no manual mode. When you drop the transmission down into manual it was just stuck on the 6th gear it would not move from there but the truck drove fine it wasn't stuck in third gear or anything. I carefully closed up the female terminals in the connector with a pair of very small needle nose pliers after I took out the red connector retainer. Fired the truck up and my manual mode was working again.

[@nicholasknutson6433]

Do you remember which pin?

[@jasonperkins9227]

Hey people I had that u0101 code.2012 3500hd Duramax. I believed it was the TMC. AFTER months of trying to find another, I found a rebuild shop. Tested the TCM said it was good. But I found the wire harness on the pass side of tranny, THAT connection was polluted with tranny fluid! It can cause all kinds of codes. Going to replace the harness in the tranny. AND do this wire check like this video.

[@hukafuk4779]

Did you happen to find a harness ? Think that’s what my problems is

[@aaronj08ar]

That connector being wet is not an issue. The entire harness including the bare connectors live in a bath of that very same tranny fluid.

[@dinoco3527]

What shop did you use to test it?

[@user-tn1hk6zm2freedom]

I have a 06 5500 allison and there is no power to the tcm connector at all. Any ideas where I should look to solve this problem?

[@Habbasio]

hi sir i have some problem.u0101. 0073 i changed e c m tcm bcm checked wiring some code can you give so info.i had pay few online gm tech no luck

[@ctraxxxas1]

hello buddy thanks for the video. I have power to 10 and 70 also have reading on ground 9 and 69 but with key on I have nothing on pin 2 and 63? any ideas where I go from there?

[@madmikesgarage4861]

Make sure your reading the connector right, apparently the newer trucks have the connector turned 180*

[@michaellevenduski7263]

I need help bud, my 2008 lmm, got the p0872 code. My trans never slipped, never beat on it, was driving normally on highway, getting off exit while it was slowing down,engine light popped and it went right to 4th gear lock. It has higher miles, so after reading code I decided to do a complete VB-internall wire harness ect. I spent 6 hours laying in snow to do it. Its my only vehicle and I have a 6yr old. So I can't be without. Test drove last night, was fine for first couple miles until I got up to 55 mph past 4th gear, and when slowing down to stop sign same thing. Engine light, limp locked to 4th gear. Same code. I'm so upset idk what else to do.

[@uwatch8378]

Thanks

[@gerald2295]

When he checked ohms he was using the diode test on the multi meter. If you do that you can get a false reading.

[@Blue_Collar_Hunter]

Mine just went out in CA stop n go traffic 😡 thanks for this info.

[@madmikesgarage4861]

Did you get your truck fixed man?

[@Blue_Collar_Hunter]

@@madmikesgarage4861 Yes I did. I had some other electronic brake issue that also went out so I had my mechanic fix that as I did the TCM myself and saved money thanks to your video. Thank you. Local trans shop wanted $1,800 to do all the aforementioned fixes.

[@madmikesgarage4861]

@@Blue_Collar_Hunter Awesome!! That's why I make the videos, glad it helped.

[@ercysuazo726]

Would this cause a no start? I got a lbz when I put key in no instrument cluster lights are on only the check engine light and it keeps saying this lost communication with tcm code that’s it I’m stumped

[@madmikesgarage4861]

I have heard this code can cause a no start, it has never happened to me though.

[@jesserousseau2481]

I have a 09 gas 6.0 and I have u0100 and u0101. Trans won't shift right. I've checked all wires and good.

[@trevmint5615]

The connector/ pigtail on my 2013 duramax is upside down. I had to flip the connector from what's in thr video to get thr same reading

[@madmikesgarage4861]

Thank you for the comment. I assumed that if the TCM was the same that the wiring would be similar. I am just a small poor guy trying to help out, I am not making anything from this.

[@mikeburdgick7289]

I'm looking to have my TCM rebuilt because they are no where to be found. I have a 2013 Duramax with a LML engine and to my understanding that the TCM's are a sealed unit and possibly not rebuildable

[@madmikesgarage4861]

Let us know how you make out. We can share the knowledge.

[@Robert-kp8rn]

Any luck on rebuilding the TCM? Having the same issue and cannot find in anywhere. Have one in backorder currently

[@mikeburdgick7289]

@@Robert-kp8rn after extensive research I found out that the vin numbers were not matching up with the TCM's and the truck's vin's number of that they were trying to repair which lead me to believe they cannot get the software updates to work. Basically it is a hit or miss on a rebuild. We decided to stick with the dealership and waiting until April of this year for a new TCM.

[@matthewharrison333]

Yea no I'm in a bit of a predicament. I need to move my truck along with my trailer by the end of March. This backorder deal is going to cause me to have some bad times. I just had this problem yesterday. Please let me know if you get your hands on anything.

[@christinelake1098]

Think it’s possible to get a temporary fix on these TCM’s.I have a 2013 Duramax as well. Don’t know if it matters that it’s a turbo diesel?

[@joekincaid9893]

Previous owne put bully dog tuner on it. It only shutters in 1st 2nd gears then cleans up

[@preston5793]

@jose rodriguez

[@aaronj08ar]

Torque converter is slipping

[@bryanrodriguez6759]

Do I have to re learn my TCM after getting a new one?

[@madmikesgarage4861]

@@bryanrodriguez6759 Yes, you need to take it to a dealership unless you can find a diesel service center that will take your vin and program it for you before they ship it to you.

[@bryanrodriguez6759]

@@madmikesgarage4861 well I got it at Ryan’s diesel too! So they programmed it to my vin. But it’s still giving me the lost communication TCM code

[@aaronperry2009]

Hey Mike. I have an LMM with EFI live, I didn’t have the truck tuned; previous owner did. How would I go about getting the tune on the new TCM from Ryan’s? Thanks for any insight.

[@joefletcher5859]

Also interested

[@aaronperry2009]

@@joefletcher5859 I talked directly to a rep from Ryan’s and here’s what he sent back “You'd need to have the autocal or V2 and tunes to re-load onto the TCM. We've had some guys honestly like how they drive with the latest calibration vs a modded one. You can always buy new TCM tuning and add later if you really need it.” So I’ll likely just use whatever is on the TCM and go that route and see how it does.

[@madmikesgarage4861]

I pulled this off of there site. **IF YOU HAVE TCM TUNING WITH EITHER EZLYNK OR EFILIVE YOU WILL BE ABLE TO RE-INSTALL YOUR TUNES ONTO OUR TCM WITH NO PROBLEMS. IF YOU HAVE CUSTOM ECM TUNING THIS WILL SYNC WITH OUR TCM WITH ZERO ISSUES** I would call them if you have any questions. When i called them them to see if they had a LBZ TCM module in stock a person answered the phone that was very friendly and helpful. I couldn't recommend them enough.

[@coryevans8350]

Is the T14A the same as the T14

[@scott2362]

I'm not getting power to my 1 or 63. What do I do?

[@madmikesgarage4861]

Check your harness for damage after you go through your fuses. There is one on the driver side dash that will cause issues for the trans if it goes bad.

[@scott2362]

@madmikesgarage4861 so I tracked all the wires down. My ignition switch is getting power and sensing power when turned on, but that fuse by the door for ignition is not getting power to it.

[@brianmoore7226]

I’ve got a stock 09 2500 duramax that goes into limp mode whenever I go into the passing gear. Any idea what would be causing this?

[@larrystaats9044]

Does anyone know where I can find a wire diagram pin number for the 2014 GMC 2500 HD Diesel the pin location is hard to see on this video. It looks like the harness pins are different maybe there the same its just hard to tell.

[@chriscowell3278]

Right. I have a 2011 6.6 with 6 speed transmission and this wire diagram/pin location is totally different that mine. He has pin connectors where I don’t and vise versa. Misleading title

[@Tortuga89R]

Ryan's Diesel programmed TCM is now $1695. ☹

[@madmikesgarage4861]

Damn!! Inflation i guess

[@2etheth]

Holy molyyyyyyyy. Not too thrilled about that lol

[@jordanbush5324]

You mentioned you were in limp mode. Were you in limp mode while hauling or daily driving?

[@madmikesgarage4861]

Just daily driving for me

[@joekincaid9893]

Why would my 09 3500 start shuttering in low take off or pulling a traylor. It seems to be transmission. Do you have any advice?

[@madmikesgarage4861]

You could check the universals in the drive shaft. You make it lucky and not have to spend much to fix it if that's it.

[@madmikesgarage4861]

You can check your engine mounts and your tranny mount too.

[@aerialboy55]

I don’t have continuity on 9 or 69 with the key on and I don’t have power to 10 and 70 key off, any ideas?

[@madmikesgarage4861]

Check your fuses on the side of the driver side dash. There is one there that can cause your TCM issues if it goes bad.

[@madmikesgarage4861]

Sorry for taking so long to get back to you.

[@valentinkeef]

Which fuses are the ones from the side I’m having same issue

[@aerialboy55]

@@valentinkeef mine wound up being TCMB fuse. I think it was under the hood.

[@aaronj08ar]

​@@valentinkeef#3 & #17

[@user-js8hh5ef4f]

My 08 dose not have wire for number 2

[@omarvalencia5299]

I’m reading the comments since my 07 nbs doesn’t have a wire in no.2 either.

[@joshuawarblow8432]

Hello what if I don’t have a #2 pin. Truck is a 08 gmc 2500hd 6.6.

[@madmikesgarage4861]

I am not sure why you wouldn't have one, i was pretty sure that all of the 6 speed trucks were this way. Are you sure you have the connector oriented in the correct way?

[@joshuawarblow8432]

@@madmikesgarage4861 Ok thank you for the help. I’m pretty sure. Start at the top with #1 and count down

[@patrickkaufman7561]

I don’t have a pin #2 either. 09 gmc 3500hd 2nd.

[@mrmotofy]

I heard a rumor the A59 is an upgrade to the A40 and A50

[@hannahwebb5653]

So what does it mean if I don't have power to 63?

[@madmikesgarage4861]

The newer trucks apparently flipped the connector upside down

[@gibsonbott7523]

​@@madmikesgarage4861 what??

[@amandaholt1991]

Whats the problem if no power in the 63 terminal

[@madmikesgarage4861]

Make sure the pin 63 socket isn't pushed out. Check your fuses and wiggle the wiring.

[@amandaholt1991]

I'm in that process right now got power at fuse

[@amandaholt1991]

My bad I believe that I was checking wrong terminal so im guessing the tcm is bad

[@madmikesgarage4861]

@@amandaholt1991 How did you make out?

[@amandaholt1991]

Ordered new tcm should be here on Monday Ordered from Dan's

[@juancarlossandoval3472]

Just replaced the transmission and this code come on and the truck has no power , even the revs don go over 3

[@madmikesgarage4861]

The TCM may need programmed to the new transmission. sounds like you are in limp mode.

[@juancarlossandoval3472]

@@madmikesgarage4861 thanks Mike , do I need to take it to the dealer or someone else to program the TCM ?

[@genarochapa3407]

Did you have a phone number from were you get the parts

[@madmikesgarage4861]

262 844 9990

[@dfreddy3141]

Nobody has one right now

[@preston5793]

I got a used one

[@joserodriguez-sy1zu]

@@preston5793 preston im interested. How can I contact you? Phone number please.

[@madmikesgarage4861]

I was lucky when i got mine, Ryan's website showed them being out of stock. I called and they had just recieved some earlier that day. They are real nice people to deal with.

[@brandonroberts6471]

Has anyone else found a place that will rebuild or has one in stock? I have one on order with the dealership. However no ETA and some have been on order since August.

[@brandonroberts6471]

​@@preston5793 a used one? I was told they need to be vin programmed. How did this work out for you? Is the TCM able to be reprogrammed ?