Volkswagen issues sales halt; CEO apologizes on emissions cheating

Volkswagen's CEO said he is "deeply sorry" for violating U.S. emissions standards and ordered an external investigation Sunday, two days after the Environmental Protection Agency (EPA) accused the automaker of purposefully manipulating emissions tests for almost 500,000 vehicles.

The German automaker  ordered its U.S. dealerships to stop selling cars impacted by the probe until its engineers can deliver a fix.

The EPA  accused Volkswagen of installing software on 482,000 diesel cars in the USA that allowed it to cheat emissions tests, potentially exposing people to harmful pollutants at levels of 40 times the acceptable standard and respiratory conditions such as asthma.

"I personally am deeply sorry that we have broken the trust of our customers and the public," Martin Winterkorn, Volkswagen's CEO, said in a statement. "We will cooperate fully with the responsible agencies, with transparency and urgency, to clearly, openly and completely establish all of the facts of this case." Winterkorn pledged to regain the public's trust.

The violations could expose Volkswagen — the world's largest vehicle manufacturer through the first six months of 2015 — to up to $18 billion in federal fines if the EPA assesses the maximum possible penalty of $37,500 per vehicle.

The violations could  invite charges of false marketing by regulators, a vehicle recall and payment to car owners, either voluntarily or through lawsuits. Volkswagen advertised the cars under the "Clean Diesel" moniker.

The state of California is  investigating the emissions violations.

EPA accuses Volkswagen, Audi of evading emission laws

"We do not and will not tolerate violations of any kind of our internal rules or of the law,"  Winterkorn said. The company's board takes the allegations "very seriously," he said.

The EPA  accused the German automaker of adopting what it called a "defeat device" to trick U.S. regulators into believing  its cars met Clean Air Act standards for nitrogen oxides. Volkswagen admitted to investigators it had installed the defeat device, the EPA said.

The EPA said impacted cars include the 2009 to 2014 Volkswagen Jetta, Beetle and Golf, the 2014 and 2015 Volkswagen Passat and the 2009 to 2015 Audi A3.

Volkswagen told dealers they cannot sell the 4-cylinder diesel versions of those cars until a fix is available, Volkswagen spokesman Mario Guerreiro said Sunday.

The sales halt could put a significant dent in the company's September sales performance. About 20% of Volkswagen's vehicle sales are diesel engines, said AutoPacific analyst Dave Sullivan.

"It totally goes against all of the marketing they have had of a clean diesel," Sullivan said of the violations. "That’s one of the biggest selling points for Volkswagen."

Consumer Reports yanks VW recommendations

"The trust of our customers and the public is and continues to be our most important asset," Winterkorn said Sunday. "We at Volkswagen will do everything that must be done in order to re-establish the trust that so many people have placed in us, and we will do everything necessary in order to reverse the damage this has caused. This matter has first priority for me, personally, and for our entire Board of Management."

USA TODAY's Chris Woodyard contributed to this story.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.