GMC Troubleshooting Questions? Ask a Mechanic for Answers
Are you sure of that code number? U1026 means the PCM has lost communication with the transfer case module. U1096 would be the code for the instrument cluster not communicating...
I'm afraid I'm not familiar with the scan tool you mention. Can it communicate with other modules in the network, or does it just read codes?
Great. Are you ready to work on this issue now?
This type of diagnosis requires on-time answers, so it doesn't quite work unless you're there with the tools.
I'll opt out and re-open your question so others can respond when you're ready. Please don't rate or reply until that time or the site will cycle this back to me.