i can not seem to locate my OBD pluggin site.

i have a '99 A8... and i thought the obd site was right underneath my right knee...

there is a spot that a plug COVER at the knee site, but when i remove the cover the only thing i see is a bolt!!!

my check engine light came on the other day when i was driving down the highway, car seems to be running ok with a slight rough idle at stand-still.

i think i found it.... it was under my LEFT knee and underneath the dash

i'm going to advance autoparts and borrow their obd scanner and will post the codes
----- when i tried to use the scanner yesterday, and of course not finding the port, the scanner said GM this and that and i think FORD as well, but NO AUDI... do i just input obd generic???