Mitsubishi Motors has admitted cheating on testing to inflate the fuel economy numbers for some of its cars. The 625,000 vehicles affected so far appear to be limited to the Japanese domestic market, but Mitsubishi has said that it is currently investigating whether the problems extend to other markets.

The cheating was uncovered by Nissan, which sells some of the affected cars under its own branding. Nissan and Mitsubishi collaborate on kei minicars, such as the Nissan Dayz and Mitsubishi eK, which have been sold in Japan since 2013. When the partnership began, Mitsubishi was responsible for the manufacture and development of the vehicles, with Nissan simply rebranding some of them for sale under its marketing umbrella. In 2015, however, Nissan took over the responsibility for designing the cars. That’s when Nissan noticed the discrepancy between the published fuel-economy ratings for the minicars versus its own measured results.

Mitsubishi admitted that its engineers intentionally manipulated its internal fuel-economy evaluations in order to overstate the efficiency of its vehicles. The company’s president, Tetsuro Aikawa, in his announcement of the manipulated results, denied that he knew of the misrepresentations until informed of the discrepancy by Nissan.

This latest scandal to affect the auto industry is eerily reminiscent of the Volkswagen emissions situation, which has embroiled the German automaker in global litigation. Volkswagen admitted to designing “defeat devices” which alter emissions results during the testing of its diesel-powered cars. During normal operation, the Volkswagen cars emit much greater pollutant levels than those registered during testing.

It is unclear, however, whether revelations of Mitsubishi’s misrepresentations will lead to litigation in the United States. If further investigation reveals that the automaker’s U.S. models were sold based on promises regarding the vehicles’ fuel economy that were not met, this could lead to litigation in U.S. courts.

After its announcement, shares in Mitsubishi traded on the Tokyo stock exchange tumbled, closing down more than 13 percent. The carmaker, the sixth-largest in Japan, confessed in 2000, and again in 2004, to systematically covering up vehicle defects, leading to a recall of almost one million vehicles.