Mr. Stadler became chief of Audi, one of Volkswagen’s most profitable brands, in 2007 after working as chief of staff to Ferdinand Piëch, the Porsche family scion who dominated Volkswagen for two decades beginning in the 1990s. Mr. Stadler left Audi in 2018 after spending several months in pretrial detention.
In 2017, Volkswagen pleaded guilty to fraud and other federal charges in Washington, after admitting that engineers rigged nearly 600,000 diesel cars sold in the United States to cheat on emissions tests. The cars were programmed to recognize when they were being tested on rollers in a lab. If so, the cars produced emissions that were compliant with regulations.
On the road, when regulators were not looking, the cars produced more toxic nitrogen oxides than a long-haul truck. Volkswagen diesels were not capable of consistently meeting emissions standards without suffering engine damage.
The software that enabled the cheating was originally developed by Audi, according to testimony and court documents, and adapted by Volkswagen engineers in 2007 after they had trouble getting their diesel engines to comply with United States standards. The illegal software was also deployed in Europe and other regions.
Volkswagen paid $4.7 billion in criminal and civil penalties as part of a settlement in 2017 with United States authorities. The company paid another $15 billion as part of a settlement with owners of VW, Audi and Porsche diesel cars.