The EC's Cesarini wants a pragmatic solution.
Toyota, General Motors, DaimlerChrysler and Fiat are under investigation by the Commission. A report from Aachen University's Institut für Kraftfahrwesen (IKA) singled out the four automakers.
The report said the four automakers were not fully complying with new block exemption regulations on sharing technical repair data. The new rules where introduced in 2002.
Paolo Cesarini, Brussels' auto industry regulator, said the investigation should be completed by the end of 2005.
Cesarini said he hopes the Commission can avoid taking legal action against the automakers.
"Pragmatic solutions can work better than punitive ones," said Cesarini, who heads the automotive section of the Commission's competition directorate.
He said it might be enough for the Commission to "express its concerns convincingly once precise facts about those companies have been collected."