[fatfash]

I mean that pinout of that small signal cable piece is different between 2011 and 2017 so if you replaced it, it would explain why its not working. I don't know if it could be software issue, doubt it. ETK gives different EPS part number for cars up to july 2016 and after that, so there could be incompatible changes in hardware, but I do not see change in ZGM at the same time, so I really don't know. If not cable and not fuse, you will have to take multimeter and check if power and bus signals arrive at EPS. Do you know part number of the new EPS you've put in?

Just confirmed what you said as i tried it with ISTA/P, though the ISTA/P was able to identify the EPS but will not program it. Don't know what to do at this point.