There ya go! And what are you doing when trying to check codes? Are you using a paper clip? The ends of the paper clip have to be bent into position so that they are aligned with the correct terminals on the diag. block. Push the ends of the paper clip into the terminals, pushing the ends to the left and down into each terminal...it's kinda hard to explain...in each terminal, there is a piece of metal that is visible, push the end of the paper clip into the terminal slightly to the left of the piece of visible metal...that's the best I can explain...and it's late...lol.