Mitsubishi Motors Corp., the Japanese automaker tarnished by a massive recall cover-up 15 years ago, owned up to another scandal Wednesday, saying employees had intentionally falsified fuel mileage data for several vehicle models.

The inaccurate tests by the Tokyo-based automaker involved 157,000 of its own-brand eK wagon and eK Space light passenger cars, and 468,000 Dayz and Dayz Roox vehicles produced for Nissan Motor Co.

The models are all so-called "minicars" with tiny engines whose main attraction is generally great mileage. They were produced from March 2013.

The scandal adds to the list of cases involving automakers inflating fuel mileage or providing faulty emissions data. It surfaced after Nissan pointed out inconsistencies in data, Mitsubishi said. MitsubishiMotors conducted an internal probe and found that tire pressure data was falsified to make mileage appear better than it actually was.

"The wrongdoing was intentional. It is clear the falsification was done to make the mileage look better. But why they would resort to fraud to do this is still unclear," company president Tetsuro Aikawa told reporters.

He and other company executives bowed in apology.

Aikawa said that although he was unaware the irregularities were happening, "I feel responsible."

The company said it would investigate whether data were altered for vehicles sold overseas. A spokeswoman for the U.S. Environmental Protection Agency was checking Wednesday to see if the agency is investigating Mitsubishi models sold in the United States. The EPA lists the 2017 MitsubishiMirage subcompact with a three-cylinder engine as getting up to 43 miles per gallon on the highway, among the highest in the U.S. for gasoline-powered cars.

It's likely that the EPA will take a closer look at Mitsubishi vehicles sold here because of the admission in Japan, said Alan Baum, a consultant in Detroit who advises automakers on fuel-economy regulations. But because the number of cars sold by the company in the U.S. is relatively small, the cars won't get a high priority, he said. Mitsubishi sold just over 95,000 vehicles in the U.S. last year, only 0.5 percent of the market.

Mitsubishi isn't the only automaker that has given faulty mileage or emissions figures. Volkswagen has admitted that 11 million of its diesel-powered vehicles in the U.S. and elsewhere had software that cheated on emissions tests, turning on pollution controls for government tests and shutting them off in real-world driving.

Hyundai Motor Co. and Kia Motors Corp. admitted in 2012 that they overstated the fuel economy of 1.2 million vehicles. The companies paid a $100 million fine to settle a U.S. investigation. They also settled a class-action lawsuit by paying owners for the cost of extra gas they would buy. Ford Motor Co. also admitted in 2014 that it overstated the fuel economy of six models. The company compensated 200,000 customers. The EPA didn't fine Ford in that case.

In Japan, Mitsubishi said fuel economy was falsely boosted by about 5 percent or 10 percent on the models, which were billed as getting 30.4 kilometers per liter (71.5 miles per gallon).

Mitsubishi Motors struggled for years to win back consumer trust after an auto defects scandal in the early 2000s over cover-ups of problems such as failing brakes, faulty clutches and fuel tanks prone to falling off dating back to the 1970s.

Aikawa was asked if the latest impropriety highlighted how the company had not fundamentally fixed itself after the recall scandal, although it had promised repeatedly to come clean.

"I realize that view exists," he said, his voice shaking slightly. "I see how difficult it can be to have compliance consciousness spread among all our employees."

Mitsubishi Motors, which also makes the Outlander sport-utility vehicle and the i-MiEV electric car, said it is setting up a panel of outsiders to investigate the latest scandal.

Production and sales of all affected models were halted, according to the companies.

Nissan said in a statement that it recently discovered discrepancies in data from Mitsubishi Motors about light vehicles it provided while assessing the current model in preparation for its next-generation vehicle.

"In response to Nissan's request, Mitsubishi admitted that data had been intentionally manipulated," Nissan said.

It said that after consulting Japan's transport ministry, it told dealers to stop selling the affected vehicles. Nissan said it is considering ways to help the owners of cars already sold.

Mitsubishi Motors shares fell 15 percent in Tokyo trading.