Volkswagen 'cheated for second time on emissions tests'
The US government has said German car giant Volkswagen cheated on emissions tests for a second time.
The Environmental Protection Agency (EPA) said the firm installed software designed to defeat emissions tests on 2014 to 2016 vehicles with three-litre six-cylinder diesel engines.
The car maker previous acknowledged rigging emissions tests for four-cylinder diesel engines.
The agency said the software has a timer that makes the cars perform differently when being tested than they perform on the road.
The EPA said the cars give off up to nine times more nitrogen oxide pollution while being driven than they do when tested.
The violations cover about 10,000 vehicles, including the 2014 Touareg, 2015 Porsche Cayenne and the 2016 Audi A6 Quattro, A7 Quattro, A8 and Q5.
The EPA said the software on the six-cylinder diesels has a timer that turns on pollution controls when testing begins, including fuel injection timing, exhaust gas recirculation rate and fuel injection pressure.
All cause the cars to emit less nitrogen oxide pollution by operating at high exhaust temperatures, the agency said. One second after the first phase of the test ends, the cars return to normal operation.
Volkswagen faces fines of up to 37,500 dollars (£24,325) per vehicle, which means up to 375 million dollars (£243 million) could be added to penalties already projected in the billions of dollars.