Hi to all! am a new comer to this AudiForum and really happy to be here... I have a 2003 Audi A4 1.8T Quattro and will be glad if any member can guide me to where the TCU is located, please. Thank you.

 

Believe it is under the passenger seat, or under the carpet somewhere on the passenger side. At least its not like mine (CVT) and INSIDE the transmission. Sorry I couldnt be more help as to the exact location, but do some searching. Its on the passenger side in the cabin though for sure. Think under the seat maybe under the carpet