I'm still learning tuning. I've only been reading the computers at this time. I have watched videos and read tutorials. I'm currently reading different years of GM computers. The first and second one was from a 2002 and 2001 Silverado and have been tuned before, the third one was from a 2003 GMC Yukon and is stock and has not been tuned before. When I hooked up the MPV12 to just read the 2003 and where it shows what system the computer is, the drop down box came up and asked to choose from a Dodge to several other systems. It didn't do this on the first two computers, is this normal or did I miss something on the first two. Remember, I'm still learning.