Volkswagen's proposed US recall to correct excessive nitrogen emissions from its 2-litre diesel cars is inadequate, California's environmental regulator said Tuesday.
The decision in effect sends the German automaker back to the drawing board for a US recall of models sold from 2009-15.
'They compounded the lie'
Mary Nichols, chairwoman of the California Air Resources Board (CARB), said: "Volkswagen made a decision to cheat on emissions tests and then tried to cover it up. They continued and compounded the lie, and when they were caught they tried to deny it."
The federal Environmental Protection Agency was due to issue its own decision Thursday on the recall proposal.
CARB was key in exposing software in VW diesels that made the cars falsely appear to comply with state and federal clean-air standards. Due to the size of the California market, automakers follow the state's regulations across the United States.
Why reject VW's plan?
The California agency said VW's recall plan "fell short in several areas" including insufficient detail about proposed repairs for authorities to make a technical evaluation.
The VW proposals, which have yet to be made public but may include installation of a catalytic converter to reduce emissions, "do not adequately address overall impacts on vehicle performance, emissions and safety," CARB said in a statement.
The rejection does not apply to VW's 3-litre vehicles.
CARB on Tuesday further gave VW formal notification of 13 specific violations of California emission standards and other regulations.
"The defeat devices on VW's diesel vehicles have caused substantial excess, illegal, and ongoing emissions of nitrogen oxides from the vehicles," CARB said.