EPA details how VW software thwarted emission tests

The software used by Volkswagen to get around environmental standards in some 11 million vehicles effectively told each car to go into a "clean mode" when it detected the car was being tested for emissions.

Details about how the automaker was able to elude emissions testing -- the "defeat device," as the software has been called -- is included in a Sept. 18 letter from the Environment Protection Agency (EPA) to Volkswagen.

That letter prompted VW to admit that half a million Volkswagens and Audis in the U.S. -- and 20 times that number of vehicles worldwide -- were actually polluting 10 to 40 times more than government agencies thought.

Volkswagen AG CEO Martin Winterkorn stepped down Wednesday in the wake of the scandal, which has cost the company billions in lost value as its stock price has plunged. Winterkorn stated that he was "shocked" and "not aware of any wrongdoing" on his part.

To read this article in full or to leave a comment, please click here