US environmental regulators order Mercedes-Benz to fix fuel economy labels on 2 C300 sedans

U.S. regulators have told Mercedes-Benz that it must correct the fuel economy labels on two of its model C300 sedans after tests found them to have lower-than-advertised miles per gallon.

The Environmental Protection Agency revised fuel economy estimates for the 2013-2014 Mercedes C300 4-matic FFV and PZEV models, the agency said Wednesday.

Testing by the agency found that the vehicles originally submitted mpg totals were off slightly. Specifically, the miles per gallon performance in city driving was originally 20 for the FFV and PZEV. The agency revised them to 19.

The EPA also lowered the PZEV's mpg performance for highway driving to 28 from 29. The revisions led to a reduction in the PZEV's combined city-highway mpg to 22 from 23.

The German automaker did not immediately respond to a request for comment Wednesday.