I've got the little "plug in tool" that puts the computer in Diagnostic mode and makes the SES light flash codes. After reading a bit, I'm under the impression all it does is short the A and B connectors together, just like the paperclip method. Does this $20 tool do anything more than the paperclip? I've noticed that the GM Service Manuals often call for grounding the A and B terminals (like mentioned above) to perform certin tests. I have an Auto X-Ray Scan tool. From what I can tell, there isn't a mode on it to ground those 2 terminals. I can pull codes, monitor engine function, but, it can't put the trucks computer in diagnostic mode like the paperclip does. Am I right about this? Lastly, the service manual talks about reviewing engine performance over a period of time. That a Scan tool can collect engine data every few seconds and somehow let you view it later. Example - I'm getting an intermitent code 44 (lean). The manual tells me to hook up the Scan tool and drive until I throw the code, then review the Integer and Block Learn at the time the code 44 was throw. Is there some way to review or download this info. onto a PC so I can view the other engine functions at the time the code was thrown? Thanks, Eric M.