Transmission issue, code U0101?

BHAMDOC1973

MEMBER
2011 MAZDA 3
4 CYL
2WD
AUTOMATIC
174,000 MILES

Is this a possible PCM issue? Code u0101. Something isn't right.

Sunday, October 23rd, 2022 AT 3:06 PM

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

The code U0101 means the TCM, is unable to communicate. Start by checking the fuses and if all are okay, I would replace the TCM. Here is the location and how to do the job in the images below. Fortunately, it does not require reprogramming. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

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Monday, October 24th, 2022 AT 11:26 AM

BHAMDOC1973

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1,575 POSTS

I see. You mean just fuses in general? So, the TCM is under the battery on top of the transmission?

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Monday, October 24th, 2022 AT 11:28 AM

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

Yes, and yes, check all fuses and let me know.

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Tuesday, October 25th, 2022 AT 1:43 PM

BHAMDOC1973

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1,575 POSTS

Can you provide the diagram to the TCM wires? I want to check the CAN wires as they may be loose, corrosion, or the pins are too loose on inside before replacing the TCM. I have seen one video where this was their issue after they probed one wire all came to life.

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Thursday, October 27th, 2022 AT 11:17 AM

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

Sure, here you go, and I have included a guide on how to check the TCM wiring and connections.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.

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