Not sure exactly but I have connected in to the port on my Copen before to read and reset engine light warnings that came up when I replaced the lambda sensor. Took me ages to find the damn thing!! I used the Rev application on my iPhone in conjunction with a ElmCanII-WLAN ODB-II connector and it worked a treat...not sure if that helps you at all narrow anything down?! Probably not I'm pretty sure however that the exact protocol is buried in the workshop manual which I think is/was available for download on this site - I seem to remember seeing some sort of spec nonsense when looking to find where the port was.
