Toyota's chairman, Akio Toyoda, apologized today, Monday, for widespread cheating in certification tests for seven car models, as the automaker halted production of three of them.

The extensive cheating involved in Japan's largest automaker included using inadequate or outdated data in crash tests, improper testing of airbag inflation and rear seat damage in crash incidents. Falsification was also found in engine strength tests.

Toyota Motor Corporation, based in Toyota City in central Japan, has stopped production of the Corolla Fielder, Corolla Axio, and Yaris Cross in Japan. The faulty tests were also found in discontinued models.

The company stated that the violations do not impact the safety of vehicles already on the roads, which include the small Corolla and luxury Lexus vehicles.

Toyoda, bowing deeply during a press conference in Tokyo, said: "We sincerely apologize."

The Japanese government began its investigation into the Toyota issue in January. The latest problems do not pertain to Toyota's production abroad.

On Monday, rival Mazda Motor Corporation also reported similar irregular certification tests and halted production of two models, the Roadster and Mazda 2. They stated that incorrect software was used to control the engine during tests.

Mazda, based in Hiroshima in the southwest of the country, admitted to violations in crash tests for three models whose production has ceased. The violations do not affect vehicle safety.

Honda Motor Company, based in Tokyo, also apologized late on Monday for improper testing, such as those related to noise levels and torque, on a range of models whose older affected versions are no longer in production, such as the Accord, Odyssey, and Fit. They added that vehicle safety was not impacted.

About two years ago, certification issues emerged at Toyota Group companies, including Hino Motors, which manufactures trucks, Daihatsu Motor, specializing in small models, and Toyota Industries, which makes machinery and auto parts.

Shinji Miyamoto, Toyota's executive officer overseeing customer satisfaction, stated that Toyota began to reevaluate its own testing procedures following the issues faced by the group companies.

The apparent collapse of testing systems at Toyota and its subsidiaries presents a significant embarrassment for an automaker that has prided itself for decades on production excellence and a corporate culture empowering workers to create "better cars than ever."

Toyoda said the company may have been too eager to conduct tests and shortened them during a time when model types were flourishing.

Toyota sells over 10 million cars worldwide.

Toyoda, a grandson of the company's founder, noted that some certification regulations may be too stringent, pointing out that such tests vary around the world. However, he reiterated that he does not tolerate violations.

Toyoda said, "We are not a perfect company. But if we see any mistake, we will step back and continue to try to correct it."