Mazda CX9 2008 Transmission Rough Shifting

Aly Diagnostician Congo City, Congo Posted   Latest   Edited  
Unsolved
Drivetrain
Electrical
2008 Mazda CX-9 Sport 3.7L (V) 6-spd (AW6AEL)
U0100 — Lost Communication With ECM/PCM "A"
U0121 — Lost Communication With Anti-Lock Brake System (ABS) Control Module
Transmission Rough Shifting

Hi,

Mazda cx9 2008 with rough shifting, AT light come on and drive letters goes blank. i can communicate with TCM and have 2 fault codes (U0100 and U0121).

I check power supply and can lines, it's correct.

Did this problem happen with anyone?!

is this a faulty TCM?!

plz advice!

thanks

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Edgar Owner/Technician
Waukegan, Illinois
Edgar Default
 

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

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Mario Owner/Technician
Whitchurch-Stouffville, Ontario
Mario Default
 

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

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Rob Owner/Technician
Nanaimo, British Columbia
Rob Default
 

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?

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Aly Diagnostician
Congo City, Congo
Aly Default
 

Hi, abs and ecm have no fault codes.

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John Instructor
Beaver, Pennsylvania
John Default
 

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?

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Aly Diagnostician
Congo City, Congo
Aly Default
 

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

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John Instructor
Beaver, Pennsylvania
John Default
 

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?

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Frank Owner/Technician
Toronto, Ontario
Frank Default
 

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.

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Matthew Mobile Technician
Bartlett, Illinois
Matthew Default
 

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…

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Stuart Mobile Technician
Blue Island, Illinois
Stuart Default
 

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.

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