The California Air Resources Board has rejected Volkswagen's fix-it plan for diesel-powered vehicles that used software to cheat emissions regulations, calling the proposed plan insufficient.

The decision covers Volkswagen vehicles powered by a 2.0L four-cylinder TDI in model years 2009-2015. The decision doesn't affect the company's 3.0L engines named by regulators.

"Volkswagen made a decision to cheat on emissions tests and then tried to cover it up,” said Mary D. Nichols, the board's chair. “They continued and compounded the lie and when they were caught they tried to deny it. The result is thousands of tons of nitrogen oxide that have harmed the health of Californians. They need to make it right. Today's action is a step in the direction of assuring that will happen."

The board rejected the plan because it contained gaps and lacked sufficient detail. The plan's descriptions of proposed repairs didn't contain enough information for a technical evaluation, and the proposals didn't adequately address overall impacts on vehicle performance, emissions, and safety, according to a CARB release.

Volkswagen officials have said they continue to work with regulators to resolve the issue, according to a statement obtained by Reuters. VW CEO Matthias Muller is meeting with EPA chief Gina McCarthy on Jan. 13.

The board will continue to investigate Volkswagen's diesel engines with the U.S. Environmental Protection Agency to return the vehicles to legally required emissions levels. The board could order a remedy from Volkswagen, and both agencies may impose fines.

Discussions between Volkswagen and regulators broke down in recent weeks, after CARB gave the automaker an extension to present a plan to recall the vehicles. A recall is still on the table, according to a CARB statement.