Investigative panel said data falsifying went on for 25 years.
Sales have plummeted, especially in Japan, where the automaker expects a 41% drop.
Penalty the first under new rules to limit the amount of heat-trapping gases cars are allowed to emit.
EPA says fuel economy last year rose 0.21 km/l over the 2012 model year.
172,000 Canadian drivers will get pre-paid credit cards to reimburse them for deficiencies in gas consumption ratings.
US environmental agency says automakers overstated gas mileage by up to six miles a gallon.