The European Court of First Instance says "TDI" designates one of the characteristics of the cars and repair services and therefore cannot be registered as a Community trade mark.

In 1996, Audi filed an application with the EU's Office for Harmonisation in the Internal Market (OHIM) for registration of the word mark "TDI" as a Community trade mark. The OHIM refused the application on the ground that the word mark was devoid of any distinctive character.

Audi then lodged an appeal with the Board of Appeal of OHIM, which was dismissed on 8 November 2001 on the principal ground that the mark was descriptive. In May 2002, Audi brought an action before the Court of First Instance for annulment of that decision. But the Court observed that signs and indications which may serve to designate the characteristics of goods or services are to be freely available to all, and may not be registered.