TOKYO — Mitsubishi Motors, 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 test 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 problem surfaced after Nissan pointed out inconsistencies in data, the company said. Mitsubishi 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.

Mitsubishi Motors struggled for years to win back consumer trust after an auto defects scandal in the early 2000s.