Although it's been nearly four years since the Volkswagen Dieselgate scandal broke, there's still more information coming out that continues to amaze. This time, it turns out Audi played a far more significant role in the scandal than anyone previously thought. The new information comes to light courtesy of a joint investigation by the German newspaper Handelsblatt and Bavarian broadcaster Bayerische Rundfunk. The New York Times then covered the German reports. It all dates back to 2007 and 2008 when Audi engineers realized the new generation of clean diesel engines they had developed would not meet stricter regulations in the US, a key market. "We won't make it without a few dirty tricks," one Audi engineer wrote to colleagues in an email.

Other emails obtained in the German investigation reveal Audi managers and engineers discussing "defeat devices" and "cycle beating." Even as far back as 2003, an Audi software developer wrote in an email that "CARB won't notice," in reference to the California Air Resources Board. CARB later forced VW to buy back or repair over 400,000 vehicles in the US. The dirty tricks didn't end there.

These new clean engines relied on urea injection to neutralize emissions of nitrogen oxides from diesels, the main pollutant the cars emitted. Because diesels were not as popular in the US as they were in Europe, VW managers were concerned owners would hesitate to refill the separate urea-fluid tanks once they were empty with its branded form, Ad Blue. The solution was to make sure the tanks would last 10,000 miles, which is roughly equivalent to Audi's required oil change time frame. This way, dealers would simply refill the tanks instead of owners as part of the vehicles' regular service.

But there was still a problem: the tanks wouldn't last long the length of the service interval if the diesels were to meet ever-increasing US and EU emissions standards. Audi managers were fully aware of this because, in 2008, they had a PowerPoint presentation indicating so. There was simply not enough room for bigger tanks, so managers decided to ration the fluid instead.

In an email dated the same year, it was written that "under no circumstances" should US owners be required to refill the tank themselves between service visits. "That would be a disaster for the entire Clean Diesel strategy in North America!" the email stated. Because of that decision, a recall was eventually issued for the automaker's V6 diesel and second-generation 2.0-liter diesels in the US. Even as late as 2017, Audi continued selling the Q5 3.0 TDI with the defeat device in Europe – two years after Dieselgate was exposed.

In a statement to the German publications and The New York Times, Audi said it could comment very little due to pending criminal investigations, but it has taken steps to prevent further cheating, such as by separating software approval from software development and establishing a whistle-blower system.

"We have undertaken a great deal to ensure that something like the diesel crisis never happens again." So far, Volkswagen has spent $30 billion in fines, recalls, and buybacks in the US alone.