Subsequent investigations by Japanese authorities led to this discovery of emissions falsification at the plants.
Japan's second-largest auto maker said it had found that the testing environments for emissions and fuel economy in final vehicle inspections at most of its factories in Japan were not in line with requirements.
The Japanese automaker said in a statement it had found that the testing environments for emissions and fuel economy were not in line with requirements, and that inspection reports were based on altered measurements. Nissan did not reveal how many cars were affected by this issue but stated that the problem was caused by inspection reports that had been "based on altered measurement values".
"Nissan understands and regrets the concern and inconvenience caused to stakeholders as a result of its [inspection process] issues a year ago. Proactive initiatives to prevent recurrence of such issues have led to the discovery of this misconduct, for which the company is regretful", the company said in a statement.
A full and comprehensive investigation of the facts outlined above, including the causes and background of the misconduct, is underway. The company has now launched a "full and comprehensive investigation", and has employed a leading Japanese law firm Nishimura and Asahi to investigate the plants involved in the scandal.
This issue came to light during the course of voluntary checks conducted by Nissan.
"Nissan understands and regrets the concern and inconvenience caused to stakeholders as a result of its kanken [final vehicle inspection process] issues a year ago".
Nissan claims that "appropriate measures" have been taken to ensure that this does not happen again in the future.
Nissan has clarified that none of its cars strays from its advertised fuel economy and emissions figures and that it will continue to search for areas of non-compliance, taking the necessary steps if more are uncovered.