Electromike: I gave the test code you sent me a try. 14230 slow & fast do not connect. I can only manage to get 9141 to init successfully.
Froggy: I know for the jetta, it provides additional data through KWP2000(iso 14230) but it is encoded in their proprietary format "VAG". Only thing is the OBDuino isn't even able to read the status of the o2 sensors, and correct me if I'm wrong but isn't that a required PID that is used when you get your car inspected?
On a side note I was thinking about trying to use my freescale chip and trying to wire up a laptop adapter so I can try out various OBD scanning programs. I need to use USB since my laptop does not have serial. I was wondering if there was anyway to use the arduino as a usb/serial adapter for the freescale chip? If not I can just use one of the various diagrams online.
Also, I found this software
http://groups.google.com/group/monoscan Which is dedicated to reading Keyword 1281, and 2000 which are the VW/Audi protocols. I might give it a try to see what data I can access from the ECu.