Automakers now complain about the steep technical challenge that the stringent standards pose. They have estimated that only about 3.5 percent of new vehicles are able to reach it, and that their industry would have to spend a “staggering” $200 billion by 2025 to comply.

A separate study by the International Council on Clean Transportation, a think tank supporting emissions controls, has estimated that the cost of meeting those standards could be overstated by as much as 40 percent. And auto industry experts have warned that a slowdown in America’s shift toward efficient cars could leave its auto market a global laggard.

John Bozzella, chief executive of Global Automakers, an industry trade group, said before the California vote that companies agreed on the need to continue to reduce greenhouse gas emissions and improve fuel economy. But he urged California to fall into line with federal rules.

“There is a more effective way forward than regulatory systems that are different,” Mr. Bozzella said. He also suggested that demand for clean cars remained relatively tiny.

What was required, he said, were standards that “balance innovation, compliance and consumer needs and wants.”

Automakers have also been critical of a California’s zero-emission vehicle program, which requires automakers to sell a certain percentage of electric cars and trucks in California and nine other states. The board voted on Friday to continue that program.

Politicians in California, one of the country’s most Democratic states, have embraced acting as a bulwark against Mr. Trump’s policies, promising to defend the state’s laws on immigration, health care and the environment. Many cities in California have broad “sanctuary” policies aimed at protecting the rights of undocumented immigrants. State law also provides some protections for immigrants from being turned over to federal authorities for deportation.