Most AWD trucks are not setup for low range. This is an issue when in 4Lo. The truck will shut down and or not up shift and or shut off 4 cylinders. The 4wd calibration has a parameters that are set just for in Lo range.

In this case the Escalade PCM may work out the best for you at this point if you can get the VATS to work.

 

VATS? From what I understand the T case is an nvg149 which is completly mechanical and has no electronic plugs that go anywhere except for a speed sensor...that's why I converted my 2wd yukon to awd...
From 02 escalade drivetrain...I believe the 03 and up escalades, denali, SS have a different T case that does require pcm programming and electronic plugs to modules I think they are borg warner 44?? Don't quite remember

 

Caleditor...what's VATS? Also what's COGS? Someone else mentioned that one but not sure what they meant?

 

VATS-Vehicle Anti Theft System. You will need to disable it when you get the pcm in your truck if you want to start it and keep it running....... When the vats isnt disabled, after you swap to another computer the truck will start and shortly die. so, it will need to be "tuned" as well....... There is no way around it buddy. Your going to have to get tuned either way.

 

Put the 02 LQ9 PCM in and do the VATS relearn procedure and it see if it will run. If you are lucky enough that the gear ratios are the same, you won't need a retune.
The only thing I can think of that might be a problem is the Escalade tune would be set up for DBW, while your Yukon is probably DBC. The values are in the tune for DBC, but not sure if it will work without changing the switch in the tune.


You are correct, the NVG149 trucks (like my C3) have a 2wd tune and there are no external sensors or modules for the AWD.