TOKYO -- Mitsubishi Electric falsified inspection data for some of its train air-conditioning equipment, the Japanese market leader revealed Tuesday, in cheating suspected of going back to the 1980s.
The improper inspections were uncovered by an internal investigation, and a probe is ongoing, the company said in a statement.
This revelation marks the latest scandal to cast doubt on quality checks in Japanese industry, with problems extending from cars to steel to earthquake safety equipment.
The problems at Mitsubishi Electric's Nagasaki works included reporting false inspection data to customers for equipment that was never checked, a spokesperson said.
"We have confirmed that there was no impact on the safety, features or performance of the products themselves," the spokesperson told Nikkei.
The company is investigating which models were affected.
The Tokyo-based industrial group, which competes with such rivals as Hitachi and Toshiba, holds a roughly 60% Japanese market share in air conditioning, signboards and other electronic equipment for rail cars, according to a company report.
The spokesperson said the improper inspections were uncovered in mid-June and reported to the Ministry of Economy, Trade and Industry.
Shareholders were not told of the problems at Tuesday's annual general meeting.