Re: Code P0455
"So is there a really simple version of this tool that just gives static readouts of stored codes in a maintenance setting, and gives the explanations of what those codes may mean?"
Yes, it is called the Factory Service Manual. I just paid $62 for the 2007 version on CD from TechAuthority, same place I bought one for my Jeep. For most here the 2004 and 2005 versions that are on line will do but my '07 is different.
I have several ways to read the codes but the FSM (as in RTFM) tells me what they mean and what the diagnosis tree is for each.
Computers and the web are just tools that make doing some things much easier than in the last millennia. Am afraid that I played my first computer game in 1957 and have been being paid for work with computers since 1966. It just comes naturally I guess.