Mitsubishi Motors Corp of Japan admitted on Wednesday that it discovered evidence that its workers cheated on the fuel economy test data for a number of its vehicle models.

The Japanese carmaker said that the falsified fuel test results involved around 157,000 light passenger vehicles with brand names eK wagon and eK Space as well as 468,000 Dayz Roox cars manufactured by Nissan Motor Co.

According to the company, the cheating was discovered when Nissan pointed to the inconsistencies of the data. Mitsubishi then conducted an internal investigation which revealed that tire pressure data was faked to make it appear that mileage performance was better than what it actually was.

This is the first time that a Japanese car company has reported misconduct which involved tests on a car's fuel economy. Last year, it was discovered that Volkswagen has falsified the diesel emission tests of its cars in some parts of the world, particularly in the United States.

News that the carmaker rigged its fuel economy tests which involved hundreds of thousands of cars also affected company shares. Mitsubishi shares tumbled down 15 percent on Wednesday after this news came out. 

The falsified tests affected four minicar models marketed solely in Japan, according to the car company. It also supplies Nissan Motor Co. bigger counterparts of the same car model.

In response to the revelation, Mitsubishi is stopping its production and sales of the affected cars.

"Taking into account the seriousness of these issues, we will also conduct an investigation into products manufactured for overseas markets," stated the car maker. It also said that it would "sincerely respond" to customers who purchased the affected vehicles and would also discuss with Nissan regarding proper compensation.

Compared to the big three car makers of Japan, Toyota, Honda and Nissan, Mitsubishi is far smaller. However, it also sells large number of vehicles globally.