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2014 E550 - W212 - U0402

Hi Leigh Sir! Would you be able to share your thoughts on what could be causing this error? How would resolve this issue? U0402 – Invalid data received – transmission control module (TCM) Probable Cause: Wiring, Defective TCM, Defective transmission, PCM

7 comments

7 Comments

Senior Leigh | 老李

Nov 21, 2020

The TCM is in the transmission case, soaked in the ATF.

You might to take a look at the video https://youtu.be/SaAqai5T8FA

Here is the document of removing the TCM from the transmission was pulled from MB WIS ⬇️

Remove-install electrohydraulic controller unit (transmission installed)

.pdf

Download PDF • 528KB

Ken Z

Nov 22, 2020

Replying to

TY 李 Sir! you are very kind.

Ken Z

Nov 21, 2020

Also, is the TCM located at the front passenger under the glove compartment? I pulled it back and saw a metal bracket which I think is where the TCM is mounted on. Are you able to share some diagrams and documents to help me diagnosis this? Much appreciated!

Ken Z

Nov 21, 2020

thanks for the quick reply! the only thing i feel is maybe a slight un-smoothness from downshifting - a little bit of a bump I would guess between 4 to 3 or 3 to 2. I was not able to delete this code with a OBD2 reader ( https://www.amazon.ca/Panlong-Scanner-Diagnostic-Reader-Engine/dp/B07RKVR4QN) My research is suggesting that transmission error codes cant be deleted with this simple ODB2 readers. Is this true? My thinking of unplugging the battery for a few days for the car to reset -- will this work?

Senior Leigh | 老李

Nov 21, 2020

Replying to

That reader can not delete the error code. Disconnecting the battery won't delete the error code.

I strongly recommend purchasing a MB Star for every MB DIYer. That's can save us lots of money. The instead solution is iCarsoft MBII for Mercedes Ben

Ken Z

Nov 22, 2020

Replying to

@Senior Leigh | 老李 thank you!

Senior Leigh | 老李

Nov 21, 2020

Hi Ken,

Have you ever felt the abnormal from transmission? If not, I suggest deleting the error code and read again after a few months. If the error code continued, you have to check everything from wiring, TCM, to transmission.