Embattled automaker Mitsubishi Motors Corp. admitted Tuesday that its method of testing fuel efficiency, which does not comply with Japanese standards, has been in use since 1991, much longer than it had previously stated.
The Tokyo-based automaker said it is investigating why its testing specialists have used the unapproved method for a quarter-century.
"We are not sure if they were even aware that it was the wrong method. When it started, they might have thought it was correct, and that thought was then passed down, so it is possible that they did it without questioning why," Mitsubishi Motors President Tetsuro Aikawa told a news conference at the transport ministry.