WASHINGTON (AP) — Volkswagen plans to withdraw applications seeking U.S. emissions certifications for its 2016 model Jettas, Golfs, Passats and Beetles with diesel engines, raising the possibility that an emissions-rigging device similar to earlier models is also included in its new cars.

VW has admitted that four-cylinder diesel cars from the 2009 to 2015 model years had software that helped the cars cheat on emissions tests. The admission came after the company was confronted by the U.S. Environmental Protection Agency and California regulators, touching off a worldwide scandal that involves 11 million vehicles.

By withdrawing the applications for the 2016 models, VW is leaving thousands of diesel vehicles stranded at ports nationwide, giving dealers no new diesel-powered vehicles to sell.

The application withdrawal was revealed Wednesday in written testimony submitted by Volkswagen of America CEO Michael Horn to a U.S. House subcommittee. It says VW was pulling its application because the cars have software that should have been disclosed to the EPA, which must certify them for sale in the country.

It also wasn't clear when VW would refile its application, but Horn's testimony said the company is working with regulators to get certification.

It was unclear late Wednesday exactly what the device does. EPA spokeswoman Liz Purchia said VW recently gave the agency information on an "auxiliary emissions control device." The EPA and California Air Resources Board are investigating "the nature and purpose" of the device, she said.

A Volkswagen spokesman in the U.S. said he didn't know what the device did, but the company said that such devices sense engine performance, road speed "and any other parameter for activating, modulating, delaying or deactivating" emissions controls.

Horn is scheduled to appear before the House panel Thursday, and witnesses are typically required to provide a copy of their prepared remarks a day in advance.

The lack of certification is bad news for American VW dealers, who were hoping to put the new models on sale soon in the wake of last month's admission the company had installed on-board computer software designed to cheat on government emissions tests in nearly 500,000 "clean diesel" cars.

For some VW dealers, the diesel models accounted for about a third of sales. Tom Backer, general manager of Lash Volkswagen in White Plains, N.Y., said Wednesday his dealership had already lost three deals with potential buyers because he couldn't get the new cars.

"It's not good," said Backer, who said he typically sells only a small number of diesels. "It's definitely a stain on the brand's image."

Thursday's appearance will be the first on Capitol Hill by Horn, a 51-year-old German and veteran VW manager who took the reins of the brand's American subsidiary last year. He is expected to face blistering questions about when top executives at the company first learned of the scheme.

Horn will tell Congress he only learned about the cheating software "over the past several weeks," VW spokeswoman Jeannine Ginivan told The Associated Press Wednesday.

He will also echo prior statements by the company's global chief executive apologizing for the cheating.

"On behalf of our company, and my colleagues in Germany, I would like to offer a sincere apology for Volkswagen's use of a software program that served to defeat the regular emissions testing regime," Horn will say, according to his prepared remarks. "These events are deeply troubling. I did not think that something like this was possible at the Volkswagen Group. We have broken the trust of our customers, dealerships, and employees, as well as the public and regulators."

Also scheduled to testify Thursday are two officials at the EPA who oversee emissions testing and compliance with clean air rules.

VW first confessed the deception to U.S. regulators on Sept. 3, more than a year after researchers at West Virginia University first published a study showing the real-world emissions of the company's Jetta and Passat models were far higher than allowed. The same cars had met emissions standards when tested in the lab.

VW was able to fool the EPA because the agency only tested the cars on treadmill-like devices called dynamometers and didn't use portable test equipment on real roads. The software in the cars' engine-control computers determined when dynamometer tests were under way. It then turned on pollution controls that reduced the output of nitrogen oxides that contribute to smog and other pollution, the EPA has said.

Only when the EPA and California regulators refused to approve VW's 2016 diesel models for sale did the company admit earlier what it had done.

Though VW and U.S. regulators have not yet announced a fix for illegal emissions under a nationwide recall, Horn will say the company is "determined to make things right."

___

Matthew Daly contributed from Washington. Krisher reported from Detroit.

___

Follow Biesecker at http://Twitter.com/mbieseck