Suzuki used illegal software to cheat emissions tests on 2.1M vehicles

In August 2019, Suzuki Motor Corporation admitted that it had used unauthorized software to manipulate emissions and fuel economy test results on approximately 2.1 million vehicles sold in Japan between 2010 and 2018. The software altered the test data to produce more favorable results.

The admission came as part of a broader investigation by Japan's transport ministry into emissions testing irregularities across the Japanese auto industry, triggered by the Nissan and Subaru scandals. Suzuki's stock fell approximately 10% following the admission.

The case was part of a wave of emissions and testing scandals in the Japanese auto industry (Nissan, Subaru, Suzuki, Mazda, Yamaha) that revealed systemic problems with how Japanese manufacturers conducted regulatory testing. The cases collectively damaged the reputation of Japanese manufacturing quality and prompted regulatory reforms.