Owners of several of the pricier Audi, Porsche, and Volkswagen models fitted with VW's 3.0-liter V-6 turbodiesel engine will have to wait a little longer to find out what VW Group will have to do to make them comply with emission regulations.

A final proposal for buybacks and possible modifications for more than 450,000 smaller 2.0-liter 4-cylinder diesel models will be released at the end of this month.

But the powerful California Air Resources Board has kicked back a VW proposal for modifications to the V-6 diesels that was submitted in February.

DON'T MISS: VW 2.0-liter diesel settlement details: buybacks, payments, modifications, fines, more

And it used some particularly harsh language to describe the inadequacies in the proposal.

CARB said VW's descriptions of its proposed modifications were "incomplete, substantially deficient, and fall far short of meeting the legal requirements to return these vehicles to the claimed certified configuration," according to a letter

Reports two weeks ago had indicated that VW thought it could make the cars comply with emissions regulations simply by modifying them. That now appears not to be the case.


The number of vehicles sold in the U.S. with the V-6 diesel is far lower than those with the 2.0-liter 4-cylinder, totaling roughly 85,000 across eight different luxury vehicle lines.

The vehicles with the affected V-6 engine are five different Audi models—A6, A8, and A8L TDI sedans; the A7 TDI hatchback; and the Q5 and Q7 TDI sport utility vehicles—along with the Porsche Cayenne Diesel and the VW Touareg TDI.

ALSO SEE: How VW's 3-liter diesel cheat worked; fate unclear for V-6 TDI vehicles

VW Group of America's Jeannine Ginivan provided the following statement on CARB's letter:

We understand that today's announcement from the California Air Resources Board (CARB) is a procedural step under California state law and relates to recall plans for vehicles with V6 3.0-liter TDI engines that were submitted previously.

We continue to work closely with the U.S. Environmental Protection Agency (EPA) and CARB to try to secure approval of a technical resolution for our 3.0L TDI vehicles as quickly as possible.

What that means in practice for owners, however, is that they will continue to wait for many more months to find out whether their vehicles can be modified to comply with emission standards.

CHECK OUT: Volkswagen diesel scandal: all Green Car Reports articles

If not, it seems likely that Audi, Porsche, and VW would have to buy back the affected V-6 models, probably using a similar formula to that agreed on for the 4-cylinder diesels, based on the cars' trade-in value before the scandal broke.

None of the three brands is presently selling any diesel vehicles in the U.S. or Canada, and it remains unclear when or if such sales will resume.

Mercedes-Benz has quietly removed a diesel version of its large luxury GLS seven-seat SUV from its configurator as well, although Range Rover is pressing forward its plans to sells diesel versions of its own luxury SUVs.


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