Volkswagen must provide an update on March 24 about how it will bring its roughly 600,000 diesel cars into compliance with clean air laws, according to a ruling by U.S. District Court Judge Charles R. Breyer.

Breyer told Volkswagen’s lawyers at a Feb. 25 hearing in California that he wants them to report back with information on technical solutions for the vehicles. He also asked for a solution regarding the status of negotiations on a settlement with owners affected by the diesel scandal, according to the Associated Press.

Volkswagen admitted to using illegal software two of its TDI clean diesel engines. The software allowed cars to pass emissions tests while emitting nitrogen oxide levels that were 40 times above the allowed limit when operating outside of laboratory testing.

Volkswagen is in settlement negotiations with Environmental Protection Agency and the California Air Resources Board, as well as the lawyers that are representing the owners of the vehicles

A Volkswagen spokeswoman said the company was working to find a solution but did not provide a timetable.