Nathan Bomey

USA TODAY

Volkswagen Group has agreed to yet another compensation and buyback package to buyers of its polluting diesel-powered vehicles, this time involving owners of VW, Audi and Porsche cars and SUVs with six-cylinder engines.

Under the agreement announced Tuesday, the automaker will buy back another 20,000 polluting diesel vehicles with 3-liter, six-cylinder diesel engines in the U.S., fix about 63,000 vehicles and pay $225 million in environmental remediation.

The company agreed to the sweeping settlement with the U.S. government and California regulators, having already agreed this fall to a nearly $15 billion deal pertaining to almost half a million 2-liter diesel cars.

The latest accord covers bigger vehicles, including Audi and Porsche crossovers, that like their smaller cousins were fitted with software to cheat U.S. standards on emissions.

The settlement with the U.S. Environmental Protection Agency, California Air Resources Board and Justice Department is expected to cost VW about $1 billion, said Cynthia Giles, EPA's assistant administrator for enforcement and compliance assurance.

But that figure does not include what U.S. District Judge Charles Breyer said is likely to be additional "substantial compensation" for consumers. Breyer is set to receive updates on that aspect in a hearing Thursday.

VW to pay owners up to $10K, buy back up to 475,000 diesel cars

"When an automaker does business in the United States it has a duty to meet the laws of the United States," John Cruden, assistant attorney general, told reporters. It also has a "duty to play fairly with its competitors and to deal honestly with its customers."

In the deal revealed Tuesday, owners of 20,000 of the oldest crossovers in the 3-liter group — diesel versions of the 2009 to 2012 Volkswagen Touareg and 2009 to 2012 Audi Q7 — will qualify for a buyback at retail value because they cannot be feasibly retrofitted into compliance.

Amounts were not available, but the 2-liter buybacks ranged from $12,500 to $44,000, adjusted for mileage, and the 3-liter crossovers may be worth more. Owners of 2-liter models who qualify for and receive a free repair will also receive $5,100 to $9,852 in payouts.

Owners of the newest 63,000 vehicles in the group will qualify for free repairs to bring the vehicles back into compliance with U.S. clean-air standards. Those models are the diesel versions of the 2013 to 2016 Volkswagen Touareg, 2013 to 2015 Audi Q7, 2013 to 2016 Porsche Cayenne and 2014 to 2016 Audi A6 quattro, A7 quattro, A8, A8L and Q5.

If VW can't come up with an EPA-authorized repair for the second group, it will be required to offer a buyback to those customers, as well.

The deal is "another important step forward in our efforts to make things right for our customers," VW said in a statement. "We are committed to earning back the trust of all our stakeholders and thank our customers and dealers for their patience as the process moves forward."

The settlement includes an additional payment of $25 million to California to promote environmentally friendly cars and an agreement by VW to introduce several electric models in the state.

“This settlement highlights the fact that cheating to get a car certified has consequences for air quality and the public’s health — and that cheaters will be caught and held accountable,” California Air Resources Board executive officer Richard Corey said in a statement.

“The mitigation in this settlement will now help California address its serious air quality and climate challenges with a focus on putting the very cleanest vehicles in disadvantaged communities where they are needed most.”

Judge Breyer, who has pushed the parties to reach a settlement under the mediation of former FBI director Robert Mueller, must still approve the deal. That is not likely to occur until the spring.

VW continues to face a criminal investigation by the Justice Department and potential charges in Germany over the emissions scandal, which erupted in September 2015.

Evercore ISI analyst Arndt Ellinghorst said last week in a research note that the criminal deal alone could cost VW about $3 billion.

Volkswagen has already set aside about $19 billion to pay the costs of the scandal, including the original consumer settlement. Ellinghorst estimated that figure includes about $1.5 billion for the 3-liter deal.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.