Suzuki Motor Corp. said Wednesday that Chief Executive and Chairman Osamu Suzuki will step down as CEO. The move comes after the automaker revealed its use of improper mileage testing methods last month.

During a news conference, Suzuki said he will not seek re-election at the shareholders meeting later this month. However, he will retain the position of chairman. “I apologize once again for the trouble we caused,” he reiterated.

Executive Vice President Osamu Honda is also set to step down. Both the changes are subject to approval at the shareholders' meeting.

Last month, the Japanese automaker had admitted to using faulty tests to calculate mileage for models going back to 2010. The testing methods used were not approved by Japanese regulators. Initially, 16 models were said to be affected but last week it increased the number to 21 models. The updated figure was 2.14 million cars. According to Reuters, Japanese investigators raided the company's headquarters last week in their probe of the improper tests.

Suzuki said it plans to introduce improvements, including better training and education for engineers and strengthening of its mileage testing systems. It would also encourage whistleblowing, it said.

In April this year, Mitsubishi admitted to falsifying fuel economy data on about 650,000 light vehicles, causing the Japanese Transport Ministry to call for carmakers to show evidence of their compliance to government testing methods.