US law firm Jones Day questioned executives at both VW and its Audi unit and has found no evidence that Stadler was complicit with the plan, which involved programming Volkswagen-made diesel engines to produce artificially low emissions when the vehicle was being smog-tested. In Audi's case, the engine type in question was the 3.0-liter V6 diesel. Officials with both VW and its Audi unit declined to comment, according to Reuters. That engine was used for the Audi A6, A7, A8, Q5, and Q7 since the 2009 model year, in addition to the VW Touareg and Porsche Cayenne. Audi also sold the VW Group 2.0-liter four-cylinder in the A3 from 2010 to 2013 and 2015. VW has reached an agreement with US regulators concerning that engine, which is also not connected to Stadler.
Last month, German newspaper Bild am Sonntag published specifics on how the 3.0-liter diesel cheated the emissions-testing process, including records that the motor was programmed to shut of its emissions-control equipment after 22 minutes of running, or about two minutes longer than typical emissions-compliance testing.
Audi said last November that it would work on a software update for the V6's emissions-control system that would be submitted to both the California Air Resources Board (CARB) and the Environmental Protection Agency (EPA), but the VW unit hasn't reached any settlement with US regulators implying that a solution was agreed upon.
Volkswagen's settlement with the EPA will cost Europe's largest automaker as much as $15 billion in the form of buybacks, lease buyouts, vehicle repairs, and investments in zero-emissions technology. VW sold about a half-million vehicles in the US that contained the so-called "cheat" software.