Mitsubishi Motors Corporation (MMC) has detailed how it falsified fuel economy tests to Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) as requested.

On investigations into four MMC Mini-cars it said its improper manipulation of running resistance to present better fuel consumption rates began with the development of the fuel-economy grade for the model year 2014 eK Wagon and Dayz (application for certifications submitted February 2013). Running resistance for other grades (standard grade, turbo grade, 4WD grade) as well as for the eK Space and Dayz Roox and each model year change were simulated using testing data from the fuel-economy grade vehicles.
During the development of the fuel-economy grade, the fuel consumption target was raised a total of five times, from 26.4km/l to 29.2km/l. Development progressed based on an overly optimistic outlook because of deep concern regarding new competitor fuel consumption levels, even though realistic attainment of the targets was problematic.
The coordinators at the time were well aware that fuel consumption meant “the factor that would give the most product marketing appeal” so they felt that the fuel consumption improvement targets requested by managers and executives were absolute.
Administrative managers in development-related departments did not communicate well enough with the subcontractor so did not confirm the real situation even though they understood the problematically high fuel consumption targets.
Based on the findings, drastic reforms are being considered in order to prevent recurrence, MMC said.
Further handling of the issue

Internal hearings suggested running resistance was improperly calculated in nine other models currently sold in Japan, as well as in other models no longer sold in Japan. The use of desktop calculations is also suspected on the RVR (ASX/Outlander Sport) and some other models, and investigations into the background and details are ongoing and will be announced separately, MMC said.

On 25 April, 2016 a special investigation committee consisting entirely of outside experts was established to investigate this matter more thoroughly, including the reasons for and details behind MMC’s use of the high-speed coasting test. After receiving the committee’s advice and recommendations MMC will formulate proper measures and will submit a separate report, it said.