Audi played a significant role in the Volkswagen diesel scandal—specifically in developing software that cheated emissions tests for diesels in Europe and the U.S.

That's a point that's only come to light in recent days, as documents just have been uncovered as part of European reports.

While engineers from Volkswagen's luxury Audi division were developing a new generation of cleaner diesel engines in 2007 and 2008, they realized that the new engines wouldn't meet stricter regulations in the U.S. "We won't make it without a few dirty tricks," one Audi engineer told to colleagues in a January 2008 email, acquired by the German Handelsblatt newspaper in a joint investigation with Bavarian broadcaster Bayerische Rundfunk.

In other emails obtained as part of the investigation, Audi managers and engineers specifically discussed "defeat devices," and "cycle beating."

As early as 2003, one Audi software developer circulated an email spoof of the Erl-King poem by Goethe, with the line "CARB won't notice," referring to the California Air Resources Board, which ultimately forced Volkswagen to buy back or repair more than 400,000 cars in the U.S.

Volkswagen TDI diesel vehicles owned by Phil Grate and family, Seattle, Washington

Volkswagen TDI diesel vehicles owned by Phil Grate and family, Seattle, Washington

The new cleaner engines Audi was developing relied on urea injection to neutralize emissions of nitrogen oxides from diesels, which is the primary pollutant that the cars emitted in excess. Since diesels weren't well established in the U.S., VW managers worried that owners would be reluctant to refill the separate urea-fluid tanks with its branded form, Ad Blue, when they ran out. So the company wanted to be sure that the tanks would last 10,000 miles, equivalent to the Audi oil-change interval, so dealers could refill the tanks as part of regular service for the cars. 

The problem is, to inject enough urea to meet tightening U.S. and European emissions standards, the tanks wouldn't last that long. 

A 2008 Powerpoint presentation reportedly shows that, with no room for bigger tanks, Audi managers instead chose an option to ration the fluid. An email in 2008 said, “under no circumstances” should American customers be required to refill the tank themselves between service intervals. “That would be a disaster for the entire Clean Diesel strategy in North America!” the email warned.

Paul Hayes with his Volkswagen Jetta TDI

Paul Hayes with his Volkswagen Jetta TDI

This is the decision that led to the recall of Volkswagen and Audi V-6 diesels and second-generation 2.0-liter engines in the U.S.

Volkswagen managers were under enormous pressure to boost sales to make the VW Group the largest automaker in the world, surpassing Toyota—a goal they never met after the diesel emissions cheating came to light. Selling more diesels in the U.S. was a key part of the strategy to meet that goal.

Fines, recalls, and buybacks have so far cost the company $30 billion, and some legal actions are still outstanding.

The Powerpoint also revealed that Audi continued selling Q5 3.0 TDI models with the defeat device in Europe as late as 2017, two years after the emissions problem was discovered in the U.S.

In a statement to The New York Times, which covered the German reports, Audi said it took time to uncover all the instances of defeat device software, and that the company has implemented "a great deal" of new procedures to prevent such problems in the future, including separating software approval from software development, establishing a whistleblower program, and ensuring that all employees take courses in compliance.

In an effort to move on from the scandal, the Volkswagen Group is committed to spending more than $50 billion, to develop 70 models and sell up to $22 million electric vehicles over the next decade.