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??