In a report, Subaru says "non-conforming" final vehicle inspections were identified in late 2017, and that the Japanese Ministry of Land, Infrastructure, Transport and Tourism demanded that Subaru undertake an internal investigation of the matter. Almost 7,000 vehicles were subject to inspection in the investigated time period, and the measurement equipment retained test data for some 6,500 of those. It showed that 903 vehicles had had their data "inappropriately altered," partially so that average data values would meet quality control standards. Subaru says that the decision to do this was made among vehicle inspectors and their foremen.
As Subaru's statement reads: "Inspectors engaging in sampling of fuel economy and emissions were instructed by their seniors that, if results for each vehicle did not meet such standards, measurement values should be altered to those that meet such standards, and, according to such instructions, the inspectors altered measurement values. [...] Even if there were no problems in comparison with the internal quality control standards, inspectors altered measurement values with the intention of reducing variance in measurement values in order to avoid questions from the Group Chiefs and the Section Chief on such variance. It should be noted that alterations were made not only to make results better, but also to make them worse." It appears that everything was done to keep the average values right.
Subaru adds: "Although the relevant laws and regulations stipulate that, in certain limited cases, measurement values could be altered in order to adjust errors caused by measurement equipment, inspectors misunderstand such adjustment method because of deficient internal rules and inadequate training. Inspectors altered measurement values by adjustment methods not stipulated in the relevant laws and regulations, without understanding that their methods were inappropriate."
Test equipment did not contain data from earlier than 2012, but Subaru suspects such tampering took place as long ago as 2002.
However, the matter will not result in recalls. Subaru says that the quality control standards are stricter than stipulated by law, and that the data alterations will not require recalls or cause quality issues to customers. Subaru has apologized, stating that it regrets the issue and has taken measures to prevent such tampering from happening again.