UPDATE: Volkswagen Fitted Defeat Device to 3-liter Diesel SUVs, Sedans

The Environmental Protection Agency notified Volkswagen on Monday that cars equipped with 3-liter diesel engines included an illegal “defeat device” designed to cheat emissions tests, broadening the already damning scanda l for the automaker.

The cars included on the notification were the 2014 Touareg, 2015 Porsche Cayenne Diesel and 2016 models of the Audi A6 Quattro, A7 Quattro, A8, A8L and Q5.

“Volkswagen has once again failed its obligation to comply with the law that protects clean air for all Americans,” Cynthia Giles, assistant administrator for the EPA said.

It’s unclear how many cars could be affected by the newly announced defeat device.

According to the EPA, cheating Volkswagen diesel cars would identify emissions tests and enter a “temperature conditioning” mode to illegally pass those tests. Those cars would alter their injection timing, exhaust gas recirculation rate and fuel pressure rates to induce higher exhaust temperatures and lower nitrogen oxide emissions. The high exhaust temperatures heat the selective catalytic reduction system (AdBlue or urea) to improve emissions scrubbing.

The “temperature conditioning” mode is timed to coincide with the federal emissions test program, and one second after the 75 initial tests are complete — which lasts 1,370 seconds, according to the agency — the vehicles switch back to “normal mode” with reduced emissions efficiency.

The EPA didn’t say whether Volkswagen admitted to the devices prior to being notified. The EPA didn’t specify whether the list of involved vehicles would grow to include older models.

A spokesperson for the EPA didn’t immediately respond to questions.

The agency, along with the California Air Resources Board, said the violations were uncovered as part of those agencies’ increased scrutiny on diesel emissions. Officials from both agencies said they haven’t identified any other cheat devices from any other automakers.

The notification could be damning for Volkswagen, who has maintained that its cheating program was isolated and relatively small. Defeat devices on another engine, across three lineups, may have been difficult to contain and may reveal more on how much Volkswagen of America knew about cars being imported to the country.

Audi and Porsche are likely to stop selling their affected vehicles in the U.S. after the EPA’s notice of violation, similar to Volkwagen’s stop-sale ordered in September. In Volkswagen’s case, roughly 1 out of every 5 cars sold was a diesel model. According to federal officials, cars already on the road are legal to drive

Volkswagen of America didn’t immediately comment on the letter. A spokesperson from Volkswagen Canada said only: “We are reviewing the EPA’s November 2nd notice and we are fully cooperating with the EPA’s investigation. No further comment at this time.”