(Bloomberg) -- Mitsubishi Motors Corp.’s disclosure that it manipulated fuel economy tests risks putting the Japanese carmaker back in a familiar position: needing help from Mitsubishi group companies to stay in business.

President Tetsuro Aikawa bowed in apology Wednesday before briefing reporters on the extent of the cheating. About 625,000 minicars produced over the past three years, three-quarters of which it supplied to Nissan Motor Co., were marketed as being as much as 10% more fuel efficient than they were by understating how much air and tire resistance they encounter out on the road.

Flawed method

A bigger issue may lie in store: Mitsubishi Motors has been testing passenger cars using a method not compliant with Japanese standards since 2002, according to Aikawa. While the company said it’s unclear whether the flawed method enhanced or reduced fuel economy, further revelations that ratings have been exaggerated may overwhelm the carmaker, which has the lowest level of cash among its Japanese peers. The company required two rounds of bailouts more than a decade ago from Mitsubishi group companies to survive a scandal involving a cover-up of deadly defects.

“Since the cover-up of recalls in the 2000s, we have tried to reinforce compliance within the company, but a compliance sense still hasn’t penetrated to every employee,” Aikawa said Wednesday. “I deeply understand how difficult it is to strengthen compliance, and I think this is a very shameful issue.”