The Volkswagen Group's dirty diesel scandal continues to expand.

In the wake of the company's bombshell admission that it used a software-based "defeat device" to fool emissions testing on its TDI diesels, we've seen the resignation of CEO Martin Winterkorn and a corporate restructuring.

Now news comes that 2.1 million cars from its Audi division are affected.

ALSO SEE: VW Group Names Matthias Müller As CEO, Announces Restructuring

While the majority of those vehicles are in western Europe, which has more lax pollution restrictions than the United States, as many as 13,000 are currently on American roads. In a statement Audi said the A1, A3, A4, A5, A6, TT, Q3 and Q5 were among the models equipped with the "defeat device" software.  

At this point, Volkswagen Group has announced no comprehensive plan to fix its vehicles to comply with Environmental Protection Agency standards. The company is facing fines of up to $18 billion dollars in the U.S. alone, and last week, the German giant retained the legal services of Kirkland & Ellis LLP. The firm recently represented BP for its negligence in regard to the Deepwater Horizon disaster off the coast of Louisiana. 

For a complete breakdown of the scandal, head to Green Car Reports. VW also has a special website (vwdieselinfo.com) providing information for concerned owners.  

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