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Mitsubishi cheating scandal expands to every model sold in Japan

 
Published May 11, 2016

TOKYO — A fuel-economy cheating scandal that began with a single line of microcars grew to encompass the entire Japanese lineup of Mitsubishi Motors on Wednesday after the carmaker admitted it had published exaggerated mileage ratings for every model it sells in Japan.

Mitsubishi disclosed last month that it had been using improper methods to test fuel economy for 25 years. It admitted the mistake after engineers at another carmaker, Nissan, discovered discrepancies in the ratings of a family of ultralight cars developed by Mitsubishi and sold by both companies. Mitsubishi did not initially say how extensively it had used the unapproved methods, whether it was on all models or just a few.

The issue centers on the way engineers calculate running resistance, the effect of the friction between tires and the road, under various driving conditions. The method used by Mitsubishi tends to result in a more flattering assessment of fuel economy and is approved in the United States, but not in Japan. Mitsubishi says vehicles sold outside Japan are not affected by the cheating.

On Wednesday, Mitsubishi added nine more models — the remainder of its current lineup — to the list of affected vehicles. The company said it was still retesting older vehicles, but it said it had confirmed discrepancies in the ratings of an unspecified number of discontinued models, too.

The company said it had even misstated the energy efficiency of a vehicle that does not use gasoline, the all-electric i-MiEV. It acknowledged that there could be problems with the ratings of every car and truck it had produced since 1991.

"I think the fact that work was being done in an insular company was one big factor," chairman Osamu Mashiko said at a news conference. He said successive Mitsubishi development teams had used the same flawed testing methods without questioning them.

Mitsubishi said discrepancies in the ratings of the nine additional models named were relatively small, amounting only to "several percent." The company said it had exaggerated the mileage of the ultralight car line sold by Mitsubishi as the eK and Nissan as the Dayz — by a much greater extent, from 5 to 15 percent.