TCCM Differences

freddyboy61

Original poster
Member
Dec 4, 2011
276
There apparently are two different part numbers for a TCCM (for a Trailblazer or Envoy 4WD), GM 12590220 fpr 2002-2005, and 24233623 for 2006-2009. Does anybody know what the differences are?
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Those years seem to follow with the addition of traction control and Stabilitrak. Maybe that's the difference.
 
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freddyboy61

Original poster
Member
Dec 4, 2011
276
Thanks for the info, I always thought the TCCMs were all the same for the entire model run.
 

TJBaker57

Member
Aug 16, 2015
2,897
Colorado
So here's something that just occured to me. Early GMT360s communicated using the SAE J1850 VPW protocol. Later editions added or switched over to I think GMLan which I further think is a CANBUS variant? Can someone who knows about this stuff confirm, expand upon,or simply comment on this? Could this be the difference in the TCCM modules?
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
From what I can tell, both the old CANBUS and GMLan ran concurrently for several years. Not sure when it started though. I found this out when I was making a benchtop interface for my Tech 2 for programming a 2008 PCM. I think that's where the CANdi comes into play. I do know that the old CANBUS was dropped 2014 onwards and the Tech 2 is useless with those vehicles.

The PCM and TCM were on the new GMLan while pretty much everything else still ran on the old CANBUS. I would guess the change happened in 2006. Maybe @limequat can confirm.

For the TCCM, I just looked on RA and they list it from 2006 to 2009 so that would be my assumption as it has to communicate with the TCM.
 

TJBaker57

Member
Aug 16, 2015
2,897
Colorado
I have only worked with a 02 trailblazer and an 04 envoy. I have no access to any newer model years.

Both the 02 and 04 I have worked with have no canbus traffic as far as I can tell, just the J1850 VPW. I communicate with the TCCM with a serial terminal app and a clone elm327 mini where I set the message header to "6C 1A F1", then send a command requesting all code statuses,,, "19 FF FF 00". If I wish to clear TCCM codes I then follow the previous request with the single command "14". Issuing these strings to a canbus or gmlan will yield only error messages. My purpose for posting this here is solely to propose that the difference in part number perhaps is due to use of different types of communication protocols??
 
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limequat

Member
Dec 8, 2011
520
I can confirm that CAN first arrived in 2008 for I6 trailblazers. For 2008 and 2009, only the ECM and TCM were on CAN. Everything else used the old 1 wire data link.
No idea about the TCCM differences. It could be something benign, like a small software update or adding a resistor to protect an internal circuit.
 
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TJBaker57

Member
Aug 16, 2015
2,897
Colorado
Just to add some more information, but no more than that....

Today I was looking into this again and confirmed that across the entire model run with the NP8 the same selector switch, encoder/motor, and front axle actuator are used. Also all the wiring is the same.

I now have 5 different part numbers of TCCM, all for the 02-05 crowd that I have acquired in order to do memory scans, locating the addresses of several data points. That task is accomplished.

Still puzzled about the difference 02-05 vs 06-09. Will add an 06+ unit to the stable next trip to the yard.
 

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