Japanese automakers Suzuki, Mazda and Yamaha admit false emissions data

Mazda Motor Corp. and Yamaha Motor Co. conducted improper fuel-efficiency and emissions tests on their vehicles, the transport ministry said Thursday.

The results came to light after the government had ordered the automakers to check their operations after revelations of improper testing at Subaru Corp and Nissan Motor Co past year.

All three have already complied with a request by the Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT) to conduct investigations into the matter.

The admissions are the latest in a string of scandals involving data falsification and testing standard breaches in Japan's key auto sector.

Mazda's inquiry, while acknowledging 72 cases out of 1,472 vehicles examined were handled inappropriately, says its investigation found "no improper adjustment or falsification of test data". The errors related to slight deviations in the speed of the vehicles during testing that should have invalidated the test results.

None of the automakers found significant problems with actual emissions and fuel economy performance of the vehicles, which were destined for sale in Japan, and do not plan any recalls.

The three companies said they certified products that tested unsuccessfully.

In a similar sample, Mazda uncovered inappropriate testing on 72 vehicles out of 1,875 units since 2014.

At Mazda, of 1,875 cars subject to the sampling inspection, improper inspections were discovered in almost 4 percent since November 2014.

Both Mazda and Yamaha apologized.

Following the emergence of the news, stock prices in Mazda and Suzuki fell by up to 5 per cent.

In July, Nissan admitted data on exhaust emissions and fuel economy had been "altered" for some of its vehicles, and a year ago the firm was forced to recall more than a million vehicles after admitting staff without proper authorisation had carried out some inspections.

That order was part of a larger inspections scandal that began when Kobe Steel was charged with manipulating data for a wide range of products.