I am curious if any of these aftermarket units can record data that you can play back. I retired from Chrysler in early 2011 but from 1992 on up I could record data and then play it back in the bigger shop computer. I could set the trigger to go of from a code or manually by pushing the button. And when it acted up you would push the trigger and it would record 45 seconds before you hit it and 10 seconds more after hitting the trigger. That way if it had a glitch and you did not hit the button until 15 seconds later you would still get the recording. Funny thing was I was the only tech in my dealer who learned how to use it and I loved it. Had a Caravan that would drop cylinders about 45 mph that drove me nuts until I took a recording and saw the speed sensor was going crazy telling the PCM it was going as fast as 504 mph ! Course the PCM was speed rated to drop cylinders an 108 mph. These aftermarket units sound like they are pretty smart from what I hear but I have never fooled with one. Ron