It is another revelation in an ongoing ordeal for the carmaker, which has been investigating the issue since the Japanese government first ordered it to in late 2017. The company had said in October that unqualified employees had performed final inspections on vehicles for as long as three decades. Subaru had to recall 395,000 vehicles sold in Japan and estimated the scandal would cost $177 million.
Subaru was not immediately available for comment. The Wall Street Journal had reported the news earlier Friday.
A similar inspection scandal crippled another Japanese carmaker, Nissan.
The most recent report said Subaru examined available inspection data for about 6,500 cars made at two plants between December 2012 and November 2017, and out of that found about 900 instances of manipulated information.
Based on interviews with employees, Subaru said the problem could date back as far as 2002, but the carmaker said it could not confirm that. It did say management was unaware of the issue.
Subaru said it is possible employees were instructed by managers to manipulate the data, perhaps to keep inspection results consistent from car to car and thus avoid questions from senior management. The company said in some cases data was altered to make results worse, not better.
It is also possible, the report said, that inspectors changed data to adjust errors by measurement equipment.
The company said there were not any alterations significant enough to merit a recall or present other quality problems.
"Subaru's management and employees will work collectively to restore lost trust and ensure
that such circumstances do not recur," the company said in the report.