An internal investigation at Mitsubishi has found that employees had intentionally falsified fuel economy data for some of its models since 1991, the company has announced.
The news came after the Japanese car-maker acknowledged last week that it had manipulated the data for more than 600,000 vehicles.
President Tetsuro Aikawa told reporters that the probe was ongoing, suggesting that more irregularities might be found.
“We don’t know the whole picture and we are in the process of trying to determine that,” he said at a news conference. “I feel a great responsibility.”
Aikawa said so much was unknown that it is uncertain what action the company will take.
He said that he did not know why employees resorted to such tactics to make mileage look better.
The Tokyo-based company had repeatedly promised to come clean after a massive scandal 15 years ago involving a systematic cover-up of car defects.
The inaccurate mileage tests involved 157,000 of its eK wagon and eK Space light passenger cars, and 468,000 Dayz and Dayz Roox vehicles produced for Nissan.
The models are all so-called “minicars” with tiny engines whose main attraction is generally great mileage.
They were produced from March 2013, and the problem surfaced after Nissan pointed out inconsistencies in data.
The car-maker found the company’s mileage goal for the minicars that had been set in 2011 was suddenly raised in 2013. Why that happened is unclear, according to officials.
Aikawa also said it was unclear how customers were going to be compensated because the extent of the cheating was still under investigation.
Mileage fraud is a violation of Japan’s fuel efficiency law for cars because buyers are eligible for tax breaks if a vehicle model delivers good mileage.
Production and sales of all affected models have been halted.
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