DSW said in a statement it was still convinced that such an investigation was the right tool for clearing up the scandal, even after its motion for a probe was voted down at VW's annual shareholders' meeting on Wednesday.

"That is why we will now enforce a special investigation in court," DSW President Ulrich Hocker said in the statement.

DSW has been pushing for an independent investigation to determine whether the 16.2 billion euros ($18.45 billion) of provisions VW set aside last year will cover the costs of the scandal and to determine if control mechanisms at the carmaker have been improved to ensure that such deliberate manipulations will not happen again.

Shareholder advisory firm Hermes EOS has also called for an external investigator to review corporate governance at VW, which is controlled by its founding Porsche and Piech families, VW's home state of Lower Saxony and the Gulf state of Qatar.

Hermes EOS, which represents large institutional investors, also wants more independent representatives on VW's 20-member supervisory board. VW on Thursday had no comment on the DSW investor group's move.

"A special investigation did not achieve the necessary majority at the shareholder meeting," a company spokesman said. "Beyond this we have nothing to say."

(Reporting by Maria Sheahan; Additional reporting by Andreas Cremer; Editing by Arno Schuetze and Jane Merriman)