My van wont pass smog

My van will not pass smog. When I take it to the smog shop, as soon as they insert their OBD2 Code Scanner my van just shuts down completely. The smog shop says to take it to a mechanic. It does not shut down when I insert my own OBD2 Code Scanner up to it. What could possibly be causing this to happen? My van was recently stolen and they broke the ignition. I put a brand new ignition in among replaced several parts with brand new ones but van still shuts down when they insert their OBD2 Code Scanner. Hopefully someone knows what the problem is. I am stumped. Thanks, Rick