Mitsubishi Motors Corp. said Wednesday it had found evidence that employees falsified fuel-efficiency data for four minicar models and that it had suspended manufacturing and sales of the cars.
"We think the manipulation was done intentionally. . . . (People in charge) wanted to make the cars look fuel efficient, but we are still investigating why they did it through an improper method," Mitsubishi Motors President Tetsuro Aikawa said during a hastily arranged news conference at the transport ministry.
The Tokyo-based automaker said the manipulated data related to rolling and air resistance tests. Smaller resistance data was set, making the vehicles appear more fuel-efficient, it said.
The manipulated data was for four models of minicars — the eK Wagon, eK Space, Dayz and Dayz Roox. Mitsubishi makes Dayz and Dayz Roox for Nissan Motor Co. and they are sold under the Nissan brand.
About 157,000 units of ek Wagon and eK Space have been sold, while Mitsubishi has manufactured 468,000 units of Dayz and Dayz Roox for Nissan.
Mitsubishi said it had stopped selling and manufacturing the four models and will discuss compensation with Nissan.
Mitsubishi also said it will check on cars manufactured for overseas markets.
According to Mitsubishi, the data manipulation came to light after Nissan conducted its own tests for the minicars and found the results differed from the data provided by Mitsubishi. Mitsubishi then looked into the issue.
The automaker, which is running new tests, estimated that the fuel efficiency gap ranged from 5 to 10 percent.
The company's shares plunged 15.2 percent on Wednesday.