2016 VW diesels have new software affecting emissions tests

WASHINGTON — Volkswagen has disclosed to U.S. regulators that there is additional suspect software in its 2016 diesel models that would potentially help their exhaust systems run cleaner during government tests.

The newly revealed software makes a pollution control catalyst heat up faster, improving performance of the device that separates smog-causing nitrogen oxide into harmless nitrogen and oxygen gases.

VW spokeswoman Jeannine Ginivan said the new issue with the 2016 diesel models, known as an auxiliary emissions control device, was revealed last week to U.S. Environmental Protection Agency and California regulators.

Regulators have not yet determined whether the code is a defeat device installed specifically to cheat on emissions tests, said Janet McCabe, acting assistant EPA administrator for air quality.

Volkswagen already faced an ongoing criminal investigation and billions in fines for violating the Clean Air Act for its earlier emissions cheating, as well as a raft of state investigations and class-action lawsuits filed on behalf of customers.

If it is determined the new issue is a second defeat device, that would call into question recent assertions by top VW executives that responsibility for the cheating scheme lay with a handful of rogue software developers who wrote the original code installed with the company’s diesel engines starting with the 2009 model year.

A congressional staffer briefed on the issue last week said VW probably didn’t need the additional software to meet government emissions standards, but that the device appears intended to ensure the 2016 cars would pass by wider margins.

Volkswagen of America CEO Michael Horn announced in congressional testimony last week that the German automaker had withdrawn applications seeking certification of its 2016 diesels because of on-board software that hadn’t been disclosed to regulators.