TOKYO -- Suzuki Motor's use of improper methods to determine fuel efficiency extends to all models that the company currently manufactures for the Japanese market, the automaker said Wednesday, widening the scope of a scandal that began with Mitsubishi Motors.
The issue concerns 16 models launched in Japan by Suzuki since 2010, including the Alto minicar and the Solio compact, as well as 11 models the company supplies to other automakers for sale in the domestic market, spanning 2.1 million vehicles in total.
The company said that the improper tests "do not apply to products sold under [the] Suzuki badge outside Japan."
Speaking on Wednesday, Chairman Osamu Suzuki apologized for not following the rules laid out by Japan's transport ministry.
At the same time, the chairman maintained that the company will keep the cars on the market, noting that the mileage data derived from the correct testing method does not differ significantly from the figures Suzuki originally reported.
The deviations amount to less than 5%, according to Executive Vice President and Chief Technology Officer Osamu Honda.
The government requires automakers to use coast-down testing, which measures various resistance factors under real driving conditions. But Suzuki calculated resistance data based on indoor testing of individual parts, such as tires and brakes.
The coastal location of the automaker's test course meant that test results tended to vary due to wind conditions. Suzuki used indoor testing data to limit such variations, the company said.
The transport ministry told Suzuki to submit a report by the end of the month with additional details on the improper testing.