2016 VW diesels have new software affecting emissions tests
Volkswagen has disclosed to US regulators that there is additional suspect software in its 2016 diesel models that would potentially help their exhaust systems run cleaner during tests.
Volkswagen confirmed that the "auxiliary emissions control device" at issue operates differently from the "defeat" device software included in the company's 2009 to 2015 models disclosed last month.
That disclosure triggered the worldwide cheating scandal engulfing the world's largest car maker.
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 vehicles was first revealed last week to US Environmental Protection Agency and California regulators.
"Volkswagen has disclosed, in the application process for the model year 2016 2.0 TDI models, an auxiliary emissions control device," Ms Ginivan said.
"This has the function of a warm-up strategy which is subject to approval by the agencies. The agencies are currently evaluating this and Volkswagen is submitting additional information."
The EPA and California Air Resources Board are investigating "the nature and purpose" of additional software on the new VW models.
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.
"We have a long list of questions for VW about this," she said at a dedication ceremony for a new heavy-duty truck testing lab in Ann Arbor, Michigan.
"We're getting some answers from them, but we do not have all the answers yet."
Volkswagen already faced an ongoing criminal investigation and billions in fines for violating the Clean Air Act for its earlier emissions cheat, 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.