I'm trying to diagnose a stalling issue in my X300. How can I test that my OBD reader is actually working? ie. what failure can I induce that will definitely be picked up by the reader?

 

Well, you can get a core P1111 or P1000 that indicates whether the drive cycle is complete or not on most scanners. And the rest of your question is sorta silly in that faults that give a correct code will be picked up by the reader. What did you mean to ask?