EPA forces Mercedes-Benz to revise MPG ratings

Mercedes-Benz has become the latest maker to see gas mileage estimates on some of its models revised downward by the Environmental Protection Agency.

The EPA says the mileage estimates were wrong in the 2013 and 2014 Mercedes C300 4-matic, both the flexible-fuel version and the PZEV low-emission version.

Compared to downgrades over the past couple years for Ford, Hyundai and Kia, the changes are minor. The FFV loses only a mile per gallon on its city driving rating, now 19 mpg. The highway rating of 27 mpg and average rating of 22 remain unchanged. Similarly, the PZEV (for Partial Zero Emissions Vehicle) loses a single mile per gallon across the board. Now, the PZEV gets 22 mpg in the city, 28 mpg on the highway and 19 mpg on average.

The EPA says it found the discrepency during testing. The valves in the C300 4-matic differed from those that had been submitted to EPA at the time of certification. Mercedes, under scrutiny of the EPA, has since made the revisions.