Ford Admits To MPG Blunder, Downgrades Fuel Economy For Six Models

Ford Motor Co. [NYSE: F] has caught an error in its calculations for EPA fuel economy for several of its small-car, hybrid, and plug-in hybrid models, and it's moving to correct that not just on window stickers, but financially, with owners of the approximately 200,000 affected vehicles.

The issue concerns fuel economy numbers that were calculated in a laboratory setting, not in real-world testing. But it does reflect and remedy some widespread complaints with some of these vehicles—namely the Ford C-Max—that they weren't returning numbers close enough to their EPA ratings.

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Ford global product development chief Raj Nair explained that the error relates to the improper measurement of something called Total Road Load Horsepower, which is a resistance level used in the lab testing for determining fuel economy ratings. The automaker also found an error in how it included aerodynamic drag in its 'virtual' wind-tunnel testing of an engineering model.

“This is our mistake”

“So this is our mistake, plain and simple, and we apologize,” said Nair, referring to the remedies the company is making.

First, Ford has notified the EPA and identified the affected vehicles. It's retested those models and has arrived at revised ratings for them.

The automaker determined the cause of the issue in March, and has been working since then, with the EPA, to retest vehicles.

Separately, Ford will make goodwill payments to owners of approximately 200,000 affected vehicles for the difference between the previous and revised ratings. The amounts range from $200 to $1,050 for owners or $125 to $625 to lessees.