In December, the Justice Department said Cummins had agreed in principle to the settlement the government said was the largest-ever civil penalty for a Clean Air Act violation. Under the proposed settlement subject to court approval, Cummins will pay $1.48 billion to the federal government and $164 million to California.

The Department said Cummins allegedly installed so-called "defeat devices" to bypass or disable emissions controls such as emission sensors and onboard computers.

(Reporting by David Shepardson; Editing by Chizu Nomiyama)