Mazda CX9 2008 Transmission Rough Shifting

Faulty tcm if there's good power ground. And data lines are good . they tent to go bad

We just did one yes the TCM goes bad on them. As long power and grounds are good and communication is clear.

I don't know for sure but maybe your post should have been listed as a QUESTION, rather than a Tech Tip. You might get more responses. Have you done any testing on the ABS module or ECM/PCMA?

Hi, abs and ecm have no fault codes.

Is this a hard fault or an intermittent one? I have had the TCMs fail, and when they do they take the whole bus down and there is no communication at all. The codes you listed, which module reported them, the TCM?

Hi, yes the TCM module reported these faults code,ABS and PCM have no faults code.

What about other modules like the Instrument cluster and Body computer, did they have any codes set? When I looked at the data schematic the ABS, PCM and TCM are common to splice pack JC36 "behind left end of dash" . Have you tried to measure the communication signals at the splice pack and the TCM during a failure?

You've done what needs to be done and I agree with the other reply that this is a 'very' common issue where the fix, for me on numerous occasions , has been the tcm.

Super common issue, but there are also some issues with relays and fuse boxes as well. It can be hard sometimes to get the vehicle to act up, but I always scope the power and ground while driving the vehicle to make sure it does not drop out. If power, ground and data lines are good it gets a TCM. They are not super expensive from the dealer (relative to other modules), and the ones I have done…

I had an almost exact same issue about a year ago and it was the TCM. Must be a common issue because the dealer had them in stock.