Volkswagen cheated a second time on emissions tests, programming about 10,000 cars with larger diesel engines to emit fewer pollutants during testing than in real-world driving, according to the U.S. government.
The German automaker installed software designed to defeat the tests on VW, Porsche and Audi vehicles with six-cylinder diesel engines, the Environmental Protection Agency and California Air Resources Board said Monday. While on the road the cars emit up to nine times more nitrogen oxide pollution than allowed by EPA standards, the agency said.
The latest charges follow VW's admission in September that it rigged emissions tests for four-cylinder diesel engines on 11 million cars worldwide, including almost 500,000 in the U.S. The so-called defeat device in the six-cylinder engines was discovered by EPA and CARB with tests put in place in late September.
In a notice of violation sent to VW, EPA officials said the automaker "knew or should have known'' that by employing the software, the cars were not in compliance with Clean Air Act emission standards.
In a statement, Volkswagen said "no software was installed in the 3-Liter V6 diesel motors to change the emissions values in any impermissible way.'' It pledged to "fully cooperate with the EPA to clarify this situation.''
VW officials have claimed only a small number of software developers in Germany were responsible for the computer code that enabled the cars to trick U.S. government emissions tests. On Monday, analysts said the latest charges call those claims into question.
"Volkswagen would do well to immediately and completely disclose all people and products involved in this deception, no matter how far-reaching,'' said Karl Brauer, a senior analyst for Kelley Blue Book, a widely used car valuation and research service.
Monday's announcement makes the notion that only a limited number of people were involved in the deception appear "even more outrageous,'' Brauer said.