I have an unsophisticated code-reader. The only thing it really does is read the codes.
From looking around, my guess is that it would be the front (pre-converter) 02 sensor, since that's the only common denominator I see from all the various codes. But that's just a guess.
[I was thinking of replacing it and seeing what happens, but looking at it in the car, it seems very hard to access and the bolts holding it in seem very rusted which would make it even harder, so not going to try it.]