i have installed a used ecu in a 1998 a4 . the ecu came out of a 2wd auto and is going into a awd manual. i have gone into the coding on the engine module and entered the correct code then clicked do it. the computer will then go to the previous screen . it pulls up and in the line where it says soft coding will appear the old code. there is the little symbol rotating like it is doing something but it never gets any further. if i click on coding again it comes up with the original code not the new one. below the code there is a window that says shop code or something like that and it is filled with zeros . what am i doing wrong ? thanks , jeff