I just received an OBD II cable, and Vag-com software.
I tried several hours to connect my pc to the S4, and it's impossible!
I decided to try with an other laptop, same problem!
Vag-com says I have to select the COM port, so I select the Com3, it's okay and it says : interface status -5 MODEM
when I try to run some options like "engine" or "OBDII compatibility", it just doesn't work... it says : possible problems -> turn the ignition on, wrong interface or something like that...
I tried then many many other programs, same thing...

What do you think the problem is ?