Signage is displayed on the side of a red 2016 Volkswagen AG Golf TDI emissions certification vehicle waiting to be tested inside the California Air Resources Board Haagen-Smit Laboratory in El Monte, California, Sept. 22, 2015. Patrick T. Fallon/Bloomberg via Getty Images

The California Air Resources Board said on Friday it was extending a deadline to approve or reject a diesel emissions repair plan submitted by Volkswagen AG for nearly 500,000 2.0 liter vehicles until Jan. 14.

On Nov. 20, VW submitted a repair plan to the Environmental Protection Agency and California Air Resources Board for 482,000 diesel Jetta, Beetle, Passat and Golf cars built between 2009 and 2015 with software that allows them to emit up to 40 times the legally allowable pollution in real-world driving.

In a letter to VW, the Air Resources Board said that after getting updates from VW on its proposed plan, it would extend its deadline to consider the plan by about three weeks.

VW spokeswoman Jeannine Ginivan said the automaker continues "to fully cooperate with EPA and CARB as we work to develop an approved remedy as quickly as possible."

VW has said that newer vehicles will require a software upgrade, but older vehicles will require the addition of new emissions hardware, along with new software.

On Thursday, VW appointed compensation expert Ken Feinberg to design and manage an independent claims program that could include buyback offers, cash compensation or other remedies. VW faces more than 500 civil lawsuits over the diesel emissions.

The EPA and California are awaiting a separate repair plan from VW by early January for 85,000 larger luxury cars and SUVs with 3.0 liter engines with a separate emissions issue.

VW halted sales of 2016 2.0 liter diesel models in September and expanded the halt to larger 2016 diesel models last month. It also applies to certified pre-owned diesel vehicles on dealer lots.

VW faces investigations around the world, including from the U.S. Justice Department, and could face up to $21 billion in U.S. fines for violating the Clean Air Act.

VW has said the software affected up to 11 million vehicles worldwide, mostly in Europe. This week, VW won approval to begin fixing 8.5 million vehicles in Europe starting early next year.

The EPA declined to comment on Europe's approval of the VW fix.

Chris Grundler, who heads EPA's Office of Transportation and Air Quality, told Reuters on Wednesday "that the Volkswagens in America are very different than those in Europe."

(Reporting by David Shepardson; Editing by Dan Grebler)