Calif. Regulators Find More Cars Evading Emissions Tests

California regulators expect to recall as many as 1,600 more Volkswagen diesel vehicles for defeating emissions tests.

The U.S. Environmental Protection Agency and the state Air Resources Board sent letters Monday to Porsche, Audi, and Volkswagen. All are subsidiaries of Volkswagen Group, which has already admitted to installing emissions-evading software in almost a half-million of its smaller diesel engines.

Regulators say the 2014 Volkswagen Touareg, the 2015 Porsche Cayenne, and several 2016 Audis have diesel engines that emit up to nine times over the federal standard, but lower their emissions when given smog tests.

"It preheats the catalytic converter, basically, so that the car on the test cycle is emitting the kinds of emissions it would emit with a warm engine," says Dave Clegern of the Air Resources Board. "Which is basically when it should be running with the lowest emissions."

The software differs from that found on the smaller diesel engines, which funneled off nitrogen oxide emissions.

The Air Resources Board plans to meet with the carmakers, which haven’t admitted to installing the software, before demanding a recall.

Nationwide, the EPA estimates 10,000 vehicles could be affected.