Ford Motor Co will offer free software updates on its hybrid models to boost their real-world fuel economy and better align with the gas mileage advertised on the window sticker, a company executive said on Tuesday.

Among the improvements, Ford plans to increase the maximum all-electric speed on those vehicles from 62 miles per hour to 85 mph. This will boost fuel efficiency by allowing the car to rely on the lithium-ion battery for a longer period of time.

The move affects the Ford C-Max and Fusion as well as the Lincoln MKZ hybrids. The changes are designed to narrow the wide range of fuel economy performance reported by hybrid drivers, said Raj Nair, head of Ford’s global product development.

“These enhancements will improve fuel economy satisfaction in several different driving conditions and modes of operation, like highway driving, short trips and use of climate control,” Nair said during a media briefing.

Owners of about 77,000 hybrid vehicles in the United States and Canada will be offered the upgrades free of charge. Nair declined to provide a cost estimate for the updates.

The move comes as Ford faces a number of class action lawsuits that claim the No. 2 U.S. automaker overstated the gas mileage on its hybrids. Consumer Reports magazine said last year that the Ford C-Max and Fusion hybrids fell far short of their promised fuel economy in road tests.

Ford has said that aggressive driving, hot and cold weather and battery performance have an outsized effect on a hybrid’s gas mileage. Hybrids show a wider range of results when compared to gas-powered vehicles, Nair told reporters.