Daihatsu has shut down production lines at its four factories in Japan while transport ministry officials investigate improper tests for safety certifications.
The shutdown from Tuesday comes a week after Daihatsu Motor Co – a unit of Toyota – announced it was suspending all vehicle shipments in and outside Japan after finding improper testing involving 64 models.
That led transport ministry officials to launch a deeper investigation into problems that apparently persisted for decades.
The safety test irregularities earlier this year triggered an independent panel investigation, which found widespread and systematic problems at Daihatsu.
It is the latest of safety and other violations found at at least five of Japan’s major car makers in recent years.
There have been no reports of accidents or deaths due to the falsified tests.
Daihatsu, maker of Hijet trucks and vans and Mira hatchbacks, said it started shutting down some lines on Monday and production stopped at all four plants in Shiga, Kyoto and Oita prefectures as well as at its headquarters in Osaka on Tuesday.
Daihatsu specialises in small cars and trucks which are popular in Japan. The company assembled 870,000 vehicles at the four plants in the 2022 financial year.
According to market research company Teikoku Databank, Daihatsu factories have supply chains involving 8,136 companies across Japan, with sales totalling 2.2 trillion sales (£12 billion).
“The longer the shipment suspension, the greater the concern about its impact on company earnings, employment and the local economy,” it said in a report.
The problems were found in 64 models and three vehicle engines, including 22 models and an engine sold by Toyota.
Daihatsu’s investigation found 174 new cases of irregularities in safety tests and other procedures in 25 test categories, on top of problems reported earlier.
The issue emerged in April when Daihatsu reported improper testing on door linings. Problems in side collision testing surfaced in May, officials said.
They also found data falsification and unauthorised testing procedures.
Speaking to reporters last week, Daihatsu president Soichiro Okudaira acknowledged the cheating on safety testing and procedures, saying it was tantamount to neglect of safety certificates.
He attributed the problems to pressure on workers to meet ambitious demands for tight development deadlines.
