Last month, Mitsubishi admitted to falsifying fuel data on some vehicles sold in Japan for more than 25 years, leading to an ongoing probe by U.S. regulators. Now, that investigation is being expanded following the automaker’s acknowledgement that it fabricated the fuel economy data on all models sold in Japan. 

The Associated Press reports that Mitsubishi announced on Wednesday that the fudged fuel records are not limited to the company’s minicars, known as “kei,” and instead may extend to all current and discontinued models sold in Japan.

While there’s currently no evidence that Mitsubishi cars in the U.S. include the same fuel inaccuracies as the 625,000 small cars sold in Japan – which included some vehicles manufactured for Nissan – U.S. regulators have already opened at least two probes into the matter.

In fact, the AP reports that the Environmental Protection Agency has now ordered additional testing to verify gas mileage on three sedans and two SUVs sold in the U.S.

The National Highway Traffic Safety Administration previously directed Mitsubishi to hand over any information on its vehicles sold in the United States.

“We’ve requested information from Mitsubishi about this issue,” a spokesman for NHTSA said at the time, declining to specify which models the agency sought data for.

Mitsubishi previously said that tire pressure data in affected vehicles was manipulated to make mileage appear 5% to 10% better than it actually was for 157,000 Mitsubishi eK wagon and eK Space light passenger cars, and 468,000 Dayz and Dayz Roox vehicles produced for Nissan Motor Co.

The falsified data was first spotted by Nissan when the company was assessing the current model in preparation for its next-generation vehicle.

A week after the scandal broke, an ongoing internal investigation by Mitsubishi found that the carmaker has used unapproved fuel testing methods for the vehicles sold in Japan for the last 25 years.

The unapproved method measured the effect of deceleration during fuel-economy testing. The method, which tends to give a more flattering mileage rating, is approved in the United States but not in Japan.

“I’m truly sorry that customers were led to buy vehicles based on incorrect fuel-efficiency ratings,” Mitsubishi’s president and CEO Tetsuro Aikawa said at a news conference last month. “All I can do is apologize.”

Aikawa says the company is unaware who ordered the cheating, but that the investigation is ongoing.

The carmaker has arranged for a panel of three lawyers to continue investigating the issue from an outsider’s point of view. The group is expected to have a report completed within three months.

Mitsubishi’s MPG mess spreads to all models [The Associated Press]

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