Toyota and Other Japanese Carmakers Say They Mishandled Safety Tests

Toyota Motor, Honda Motor and other top Japanese automakers said on Monday that internal investigations found they had mishandled vehicle testing on dozens of modelsover the past decade.

Toyota said it failed to gather proper data when doing pedestrian and occupant safety tests for three models, including its popular Yaris Cross sports-utility vehicle. Honda and Mazda Motor said they had identified problems related to the testing of several models, too.

The automakers, which had been told by the Japanese government to open the investigations, said the testing failures would not affect the performance or safety of their vehicles and that customers could continue to use them normally. Still, Toyota said it would temporarily halt shipments of three of the affected models it produces in Japan. Mazda said it would suspend sales of two Japan models.

The testing problems revealed Monday by Toyota, Honda and Mazda were conducted in Japan to meet the Japanese government’s certification standards. The vehicles at issue were sold in Japan.

Suzuki Motor and Yamaha Motor also said on Monday they had found inadequate testing in the past.

The disclosures from Toyota and others add to a lengthening tally of testing and certification problems Japanese automakers have faced in recent months — issues that people in the industry worry could impact consumer perceptions of the quality of Japanese cars.

In December, an internal investigation at a Toyota subsidiary, Daihatsu Motor, revealed that most of its vehicles had not undergone proper collision-safety testing. The following month, another Toyota unit suspended all of its engine shipments after an investigation revealed it had falsified figures concerning engine power.