In a statement issued by the company, the automaker said vehicle inspection trainees, prior to becoming fully qualified inspectors, would often perform the required checks and use their supervisors' certification seal.
At a press conference, Yasuyuki Yoshinaga, Subaru's CEO, told Reuters, and other news organisations, this process was used by employees at this factory for over 30 years without knowing that it ran afoul of Ministry of Land, Infrastructure and Transportation (MLIT) rules.
Subaru is keen to point out "vehicles for export to overseas markets are in compliance with inspection rules of each country and not affected by this matter".
Yoshinaga noted while this latest scandal probably won't affect the company's sales in overseas markets, "I'm ashamed that our company has played a role in shaking public trust in Japan’s manufacturing culture".
The automaker says it is "considering a recall campaign" for vehicles possibly affected by this latest controversy. If this goes ahead, around 255,000 Forester, Impreza and Legacy models sold in Japan will be recalled at a cost of around five billion yen ($56.7 million).
Subaru discovered the flaw in its inspection procedures after the MLIT ordered automakers to review their processes after Nissan admitted, at the end of September, to using unqualified inspectors.
Nissan temporarily halted sales in Japan for a few days after it discovered the problem. It has since issued a recall for all domestic market vehicles produced in-house between October 2014 and September 2017, totalling approximately 1.21 million vehicles.