Engine maker Cummins Inc. will recall 600,000 Ram trucks as part of a settlement with federal and California authorities that also requires the company to remedy environmental damage caused by illegal software that let it skirt diesel emissions tests.

New details of the settlement, reached in December, were released Wednesday. Cummins had already agreed to a $1.675 billion civil penalty to settle claims – the largest ever secured under the Clean Air Act – plus $325 million for pollution remedies.

That brings Cummins’ total penalty to more than $2 billion, which officials from the Justice Department, Environmental Protection Agency, California Air Resources Board and the California Attorney General called “landmark” in a call with reporters Wednesday.