It is using off the shelf software (ECUTalk, Conzult, a couple others). If one of these programs were open source maybe I could decipher how to read/write from the ECU, but I can't find any that are.
As for programming on the PC - i have zero experience with most PC programming, especially when it comes to hardware input/output. The arduino is actually a little easier for me, since I did have a C+ class back in college. I'm not good by any means, but at least part of the time I can understand the code.
There have been a few other posts on here about this exact topic, and the ones I have found have kind of died without a resolution ever coming about (or if the problem/program was resolved, they never posted back)- so there is a chance people out there are trying the same thing or have done the same thing. I have seen videos on youtube of people using an arduino to communicate with their nissan Consult interfaced ECU, but unfortunately non of those videos post a link to source code, or the link is dead, and archive.org can't bring it back...
Someone out there has done this successfully, I just need to find who.
Any help anyone can give would be awesome. I'm even willing to donate some $$ for some help. Time isn't cheap, and for someone who isn't interested to look through libraries, code, and protocol to figure out why it's not working and how I can make it work is a lot to ask.