U.S., California reject Volkswagen's proposed fix for diesel cars

DETROIT—U.S. and California regulators have rejected Volkswagen's proposed fix for most of the vehicles involved in its emissions scandal, dealing another setback to the German automaker as it tries to clean up the diesel crisis.

The Environmental Protection Agency and California Air Resources Board (CARB) — known as CARB, which jointly exposed the Volkswagen violations — said independently that they had rejected the automaker's recall proposal for 2-liter diesel cars.

CARB went a step further, blasting Volkswagen's plan and issuing a notice of 13 violations.

The move comes a day before Volkswagen CEO Matthias Mueller is set to meet with EPA administrator Gina McCarthy in Washington, D.C., to discuss the potential fix.

Mueller told reporters near the Detroit auto show on Sunday that he was hopeful the company would win approval for its proposed fix. But CARB's move means the company may have to go back to the drawing board.

"The proposed plans contain gaps and lack sufficient detail," CARB said Tuesday in a statement. "The descriptions of proposed repairs lack enough information for a technical evaluation; and the proposals do not adequately address overall impacts on vehicle performance, emissions and safety."

EPA said: "EPA agrees with CARB that Volkswagen has not submitted an approvable recall plan to bring the vehicles into compliance and reduce pollution. EPA has conveyed this to the company previously."

Volkswagen noted in a statement that the rejection applies to a plan submitted to regulators in December.

"Since then, Volkswagen has had constructive discussions with CARB, including last week when we discussed a framework to remediate the" issue, VW said. "We are committed to working cooperatively with CARB and other regulators, and we plan to continue our discussions tomorrow when we meet with the EPA."

Volkswagen has admitted to rigging up to 11 million diesel vehicles worldwide with software to cheat emissions standards, including some 580,000 in the U.S. ranging from the 2009 to 2015 model years. In the U.S., 500,000 cars with 2-liter diesel engines are affected, and another 80,000 bigger vehicles with 3-liter diesel engines are involved.

CARB said the company's violations include failure to comply with emissions standards or test procedure and invalid certifications.

Many of the cars involved in the scandal are likely to involve a software fix and hardware changes.

Volkswagen U.S. CEO Michael Horn told reporters Monday at the North American International Auto Show that the fixes would not be completed until the end of 2017.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.