The Volkswagen Group's work with illegal "defeat device" software goes back even further than originally thought, a recent report found.

Audi developed software to alter the emissions of diesel engines in 1999, but apparently never put it into production vehicles.

However, that work may have formed the basis for the software that was eventually used years later in Volkswagen TDI models.

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The Audi "defeat device" stemmed from an attempt to reduce noise from diesel engines, according to German business magazine Handelsblatt (via The Drive).

Audi engineers developed software referred to as "acoustic mode" or "acoustic function" for engine-control systems to get diesels to run more quietly.

However, those engines also produced higher nitrogen-oxide emissions when running in this mode.

2010 Audi A3 TDI

2010 Audi A3 TDI

So the engineers also programmed the "acoustic" software to deactivate during emissions tests.

The Handelsblatt article, which cites anonymous company sources, claims this software trick was never used in production cars—but that several of the engineers who worked on it were subsequently transferred to VW's own diesel programs.

There they worked on the EA189 2.0-liter four-cylinder engine that was later found to have "defeat device" software.

While combing through documents as part of a VW-commissioned investigation, the publication says, U.S. law firm Jones day found VW engineers had used the Audi codename "acoustic mode" in correspondence.

Jones Day also "scoured Audi's ranks" but couldn't find anyone directly involved, the article noted.

Audi A3 TDI compacts sold in the U.S. for model years 2012, 2013, 2014, and 2016 used 2.0-liter four-cylinder turbodiesel engines shared with various VW models.

2015 Audi A3 TDI, New York City, Nov 2014

2015 Audi A3 TDI, New York City, Nov 2014

Continuing investigations also unearthed a PowerPoint presentation from 2006 detailing the use of "defeat device" software.

Company executives were aware of cheating then, but repeatedly rejected calls to stop using the illegal software, unnamed sources recently told The New York Times.

That presentation reportedly showed that the conditions for laboratory testing were predictable, and specified how software could be developed to identify them.

It is not clear how widely VW circulated the presentation, but it indicates that at least some managers were aware of the "defeat device" software as it was being developed for production cars.

"In view of the ongoing external investigations, please appreciate that we are unable to comment on the content of this article," Audi spokesman Mark Clothier wrote in response to a request by Green Car Reports for comment on the Handelsblatt article.


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