The PLX Kiwi has all sorts of features, and supposedly includes a code reader...
The Kiwi Manual
I haven't had/taken the time to mess with all of the features so I'm not too knowledgeable about all of that. I've a 4-hour trip(1-way) ahead of me this weekend, and during some of the driving I'd like to find out more about the various functions.
It is pretty much plug-n-play, but I noticed that the vehicle has to be on when you go to plug it in and turn on, or else it will error... after its plugged in and the vehicle is off, it will go to 'sleep'.