Causes and Fixes U0101 Code: Lost Communication with TCM (Transmission Control Module)

How to fix a U0101 engine code: Lost Communication with TCM (Transmission Control Module)
Diagnosing a U0101 can be difficult and time-consuming.
DTC U010 is set when the transmission control module is unable to receive or send messages to the controller area network (CAN).
The CAN (Controller Area Network) is a protocol to allow the TCM and ECM modules, as well as other devices, to communicate with each other.
Symptoms
⦁ Multiple Warning Lights / No Gear Indicator
⦁ Vehicle will not shift
⦁ Vehicle stays in one gear (usually 2nd or 3rd) or in limp mode
⦁ Scan tool won’t communicate with the TCM
Possible Causes of the U0101 Code
⦁ Alternator Charging or Battery Issues
⦁ Blown Fuse
⦁ Wiring Open or Short
⦁ Problems with the TCM circuit
⦁ Problems with the data CAN bus
⦁ Faulty TCM
www.backyardmechanic.org
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[@adamkelly6264]

mate I just wanted to let you know these three videos saved me from pushing my amarok into the f*cking sea. Thanks!

[@djfazher]

Thank you for the information!

[@davepatt6018]

Thank you for the info

[@felipeisacchar2957]

Great información tanks

[@VegasModel]

Hey I want you to know I really appreciate this video I've been trouble shooting my TCM for months after all this removing soldering etc and fixing it myself it would only be temporary.. but now I know why. Thank you.

[@Elcapulove]

Good afternoon family and good health to everyone especially MENTAL. Thank you very much. 🙏

[@Sebastian-dx2xg]

I’m getting a parasitic draw from my TCM-BATT fuse. It’s draining my battery. But I’m not experiencing any shifting problems

[@Jim-re3sr]

2006 4.6 explorer. Failing coil pack interfered with pcm to tcm. Harness travels next to coil. Replaced coil pack solved the issue. Great video

[@katyreesimpson8742]

Just saved my ass thank you!!!

[@americanpatriot5836]

What was your problem just curious?

[@49dsa505]

Thank you for the info!

[@Renegar87]

Great video

[@weerebuildz4427]

Hey need some help I am rebuilding a 2018 Audi S5 for my channel and i am getting the same fault codes but still can not find the reason to get the car to start and need your help.

[@stevelatronica6025]

after a rebuild on the 4L60E transmission, its now throwing two codes P0826 and U0140. Any ideas? Thanks for the awesome videos!

[@Alexmanzophxsuns]

I have a jeep 2006 it showing transmission over temp but I waiting for my new computer to come hopes it works

[@rafyperalta9246]

Thanks I was able to solve the problem with this video

[@FernandoFlores-ry2iw]

What was wrong with yours

[@felixpolkey8449]

Can you tell me where the tcm is located in a 2014 Toyota Camry SE ,4cyl

[@sr25jd]

Had the battery out of a 2011 Lin Navigator for about 1 year replaced started and then the anti theft system the person that worked on the Lin prior had removed fuses I replaced those now the gear shifter won’t come out of park I replaced the brake light switch and still won’t come out of park

[@SaeedAfrooz7]

Hi My car have problem with tcm When I start my car it’s ok for 1 hour and after that the gear only shows (p-n) not go to the (D-R) when I turn of my car and turn on its ok for one time change gear after that same issues Will appear

[@28samz]

What about U0122 Lost Communication With Vehicle Dynamics Control Module (Corvette)

[@danamcintyre3565]

For starters that one of the biggest reasons I don't work on these late model cars, unless you have been schooled on it or have just enough knowledge to understand what does what, you better off taking it to a professional to have it fixed !

[@henm4975]

CURRENTLY dealing with this on my 2014 3.6 impala, it fuking sucks......i have no way of diagnosing but by checking the wires for resistance/continuity.....every module, every wire, every connector.....so far all my 2500, 2501 circuits are good....i hope its an easy wire fix. i lost 6k on a transmission shop that just started swaping the most expensive prts hoping for the best, next thing you know, i get U0101 for the 3rd time.....they say dont bring it back. had they done their job and proper diagnosis I coud be working.

[@xPlzid]

So my headlights low beam was flickering when this happened, fixed some shorts, there was a blown fuse that I have now fixed. Can’t find anymore shorts and the grounds on my car have been cleaned and everything. Have had water leak in to the passenger side where the ax blower motor is at and where the ecm seems to be located at. Will be replacing ecm and inspecting harness to make sure but this has really been a nightmare on my already pos g35

[@americanpatriot5836]

I have a 2002 infiniti i35 with driver and passenger side floor board soaked and can’t find where its coming from and also a hard shift into 2nd gear sometimes.

[@d-blareo8018]

I had an APR ecu flash on Thursday on a 2012 Audi A7. I drove the car home fine. I put the car cover on, and let it sit until Saturday. I got in it and drove down the street, stopped to check the mail, and it wouldn't go back into gear. The battery was replaced by the previous owner in November of last year, the fuse for the transmission is good, and the car starts fine. I used by BlueDriver and got the U0101 code along with 35 other codes. All of the codes cleared except the U0101. Any idea if the ECU upgrade may have caused the TCU to fail? Do you know if the TCM is disconnected during an ECU flash?

[@mikey13b]

Did you end up finding the cause of the fault code?

[@kwamepaul4418]

can u0101 and u0402 DTC be the transmission failure. its in limp mode in forward gears and reverse takes about 80% pedal pressure to move.

[@HVAC_Mechanic]

It is possible, but more likely, there is a power or wiring issue or an issue with the TCM.

[@newprep3661]

2013 impala. Very low power, not shifting to high gear, random electrical issuesfilters and fluids are fine. Reving to 3000 rpms at startup, any thoughts?

[@incith]

"random electrical issues"

[@Vtoq]

2014 Chevrolet Captiva - Check engine light would occasionally come on and eventually received U0101 code. Still looking for solution, most likely think it is a blow fuse since battery was just replaced and issue is still ongoing even before changing the battery.

[@incith]

Look at the fuses then?

[@mariachiwaula7140]

My VW Polo has U0101 and U111100, no gear display, shifter won't move out of park. Where can I check

[@lovisharora7250]

Take it to the mechanic

[@sirthomas5220]

Dealing with this issue on a 2016 impala…. It comes and goes…. Had the wires replaced and it worked for 8 months…. Problem is back and I’m trying to avoid a 3k fix

[@williammerrow]

I've seen a fuse block have bad connection. Check from the back side connections to the top side connections.

[@juanojeda8069]

Mi car was the battery do not hold the charge because winter and storage car. Mercedes GLA 250

[@Joe-rv3ud]

Battery died one day and after getting it replaced it’s doing this. Can i narrow it down with that?

[@henm4975]

maybe it wasnt the battery then

[@beckhamsfamilyjourney]

2013 chevy silverado 3500hd. How do you rest the TCM? I did the " remove the battery connection for hr" and nothing. It's not dirty or oily? All fuse are good. The dealership said I had to drive it in for them to look at it lol SHE DOESN'T MOVE FOOL! (The guy hug up on me). So is there a do it yourself? I know getting a new one it has to be programmed to the truck, so I still have to take it somewhere 😅

[@beckhamsfamilyjourney]

Also it has a sweet but nasty smell to it

[@mikey13b]

did u end up getting this fixed?

[@mikey13b]

@@beckhamsfamilyjourney if so where was the issue?

[@beckhamsfamilyjourney]

@@mikey13b the Circuit board fried

[@MegaNeet7]

I have an issue with a Chevy Cruz like this I can reverse at full speed, but when I go into gear, it starts slow. I’ve actually moved the car because I had to move and I didn’t wanna pay a towing service and I drove it 6 miles with a friend in front and a friend and back and once I got up to speed about second third, it was all right. I didn’t try to push it anymore than 48 miles an hour, but all in all I’m just trying to figure out what direction to go with this because I’ve replaced coil packs. I’ve actually replaced the engine catalytic converter radiator almost everything on a car so I’m just kind of lost.

[@HVAC_Mechanic]

It sounds like it is in Limp Mode. There should be codes that point to the issue. If the code is a U0101, then it can be hard to troubleshoot.

[@MegaNeet7]

@@HVAC_Mechanic that’s exactly it and I found in the front end of my transmission that’s where the Tcm i’m not the most knowledgeable on cars, but when I called a transmission shop, the guy was trying to tell me that mines was inside. My transmission wouldn’t that technically mean it’s mounted on the outside legit like behind my radiator fan On the driver side

[@HVAC_Mechanic]

The TCM can be located inside the transmission and be built into the valve body. If you think it is a computer issue, before replacing it, I would be sure to check all the wiring, fuses, and be sure the alternator is charging correctly. Like I said though, this code can be hard to fix.

[@GodessIsabelRaina]

I got a new battery. could it be that they put it in incorrectly❓️🤔 I had codes read on my vehicle and that one popped up. The only lights that I've been dealing with is engine power is reduced. I had my throttle body cleaned by Chevrolet and it's running even crappier so I've decided to figure out these codes for myself🙄

[@rscrevolutionpking7143]

Nah pretty much no way to put a battery on incorrectly, negative to negative, positive to positive, pre sure if you put the negative to positve and same with postive to negative all your wires just fry and youll definitely know if it does, theyll melt or something, dunno never been dumb enough to do it, just seen videos 😂 but check your spark plugs and coils, see hkw they look, if theyre crusty, bunch of oil gotten to them then could need new spark plugs and/or coils, had a car that went into limp mode due to that, changed them and ran normal, also check for any air leaking from the intake hose on the throttlebody, maybe leaking and not getting enough air if its runnibg worse since theyve cleaned it, id tell ya to check the throttlebody but unsure how mechanically minded you are and got to be careful with that as they go directly to your engine and the butterfly flap inside it can sometimes snap off into it if youre not careful

[@rscrevolutionpking7143]

Is it idling up and down alot? Not staying consistant in revs? Like goto 500, end up stalling or jump to 2000, then 1000, then 1500 etc etc

[@philswift791]

A cheap signal generator is an amazing tool to use.

[@LatifKassim-sv2uk]

Hello

[@EdAguirre-zf6lg]

Ok

[@constantinmilitaru]

Replaced the TCM and it’s a no start no crank. The new TCM is bad… 13 pins connection oil coming out… god… also don’t forget to disconnect the battery…

[@aaronj08ar]

Oil coming out of there is fine. All those wires terminate in the oil bath, they're not shorting out at the connector because of the oil.

[@supermomxt]

You have to have it programmed with your vin number at a dealership or a shop that can if you put a new one in.

[@jdmtechllc6589]

@@aaronj08arVERY BAD ADVICE

[@moenycn6c]

I have the same issue I changed a new tcm and the car no crank no start

[@SaulPaez-ed7go]

I change the tcm but i have c0100 and p0722 codes do i need to reprogram? Because with mi old tcm i don't have that codes

[@treytonmiller8407]

My 2022 dodge charger lights won't illuminate on the shifter, won't start and has the service transmission code

[@lovisharora7250]

should be under warranty, take it to the dealer

[@GuadalupeMartinez-sl2ee]

I have this code on my 08 jeep grand Cherokee nobody can figure it out

[@user-dn8nm4qz5x]

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[@freddyg9026]

why do you talk so slow?

[@curyman000]

Why do you talk fast?

[@deadly1360]

He doesn't, stop doing bumps and the world might slow down buddy. 👃❄️

[@SaeedAfrooz7]

Hi My car have problem with tcm When I start my car it’s ok for 1 hour and after that the gear only shows (p-n) not go to the (D-R) when I turn of my car and turn on its ok for one time change gear after that same issues Will appear

[@HVAC_Mechanic]

It needs to be troubleshooted to know the cause, but often, when there is no issue when starting, but after the engine gets hot, there is an issue. The TCM has a bad contact or solder joint on the board. This is just a guess, but I have seen it before.

[@SaeedAfrooz7]

I changed the tcm fuse , but the problem is still there , what may cause ? There is no issues code to know what’s wrong with the car no check light ! After one horse ride the problem coms and gets worse , Every think ok the gearbox is so soft , but when gets hot when I want to change the gear it’s only go to (n-p) when I turn of it ok only for one more time