Ford has already faced the music regarding its Fusion and C-Max hybrid’s advertised mpg versus real world, and today the company admitted an error while substantially downgrading mpg for all its 2013-14 regular full hybrids and plug-in Energi models.

Conventionally powered Ford Fiestas were also adversely affected, and the root cause, said Ford, had to do with engineering tests that were mis-calibrated. Ford said it discovered the mistake and volunteered the information to the U.S. EPA.

SEE ALSO: Ford Cuts C-Max EPA rating to 43 MPG Combined

The government agency then tested the vehicles again, said Ford, and lower window sticker mpg ratings are now being issued along with goodwill payments to around 200,000 customers.

“This is our error. When we see an issue, we address it,” said Raj Nair, Ford group vice president, Global Product Development. “That is why we notified EPA and lowered the fuel economy ratings for these vehicles.”

Ford bold-faces the combined score, but note all scores – city/highway/combined - are affected.

Ford bold-faces the combined score, but note all scores – city/highway/combined – are affected.

Ford said it also re-tested its entire line-up, said the rest were OK, but Ford and Lincoln hybrids and Fiestas were downgraded in city, highway and combined mpg scores, and MPGe plus all-electric range estimates for plug-ins.

The error, Ford said, came from a factor called “Total Road Load Horsepower” (TRLHP).

TRLHP is a vehicle-specific resistance level used in dynamometer testing of the vehicle that determines fuel economy ratings.

It is established through engineering models that are then validated through vehicle testing, including on a physical track. These track tests are called “coastdown” testing.

This method is normally a more reliable way to test, said Ford, and it is an industry practice widely used and approved by the government.

As part of routine checking of production vehicles – as opposed to pre-production vehicles – Ford said a Fuson Hybrid was found not to match up in coastdown testing. Here, Ford found the TRLHP did not match the values used for the dynamometer testing.

“Upon further testing, Ford also discovered an error specific to how we correlate wind tunnel results into the TRLHP model,” said the company in a statement. “Ford’s error was the result of a recent process change, which the company has since corrected. Ford has now validated through physical vehicle testing the TRLHP for the vehicles affected by this error and also has instituted enhanced validation tests for future vehicles to prevent reoccurrence of this error.”


Ford said dealers will be getting new window stickers to affix in the next six days.

It also will pay goodwill payments (see charts) to lessees and purchasers of around 200,000 cars.

Fleet owners outside the U.S. will be contacted by their local Ford reps, said the company.

“Ford is absolutely committed to delivering top fuel economy and accurate information,” said Alan Mulally, Ford president and CEO. “We apologize to our customers and will provide goodwill payments to affected owners. We also are taking steps to improve our processes and prevent issues like this from happening again.”