A view shows a Suzuki car dealership sign in National City, California November 6, 2012.Reuters

After fellow Japanese car-maker Mitsubishi Motor pleaded guilty to having fudged fuel efficiency data, Suzuki Motor Corporation came under spotlight for allegedly using incorrect fuel economy tests. The company in a statement denied cheating in the test, but admitted that some discrepancies were found in the automobile emission and fuel efficiency testing process between the regulation by Japan's Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the method carried out by Suzuki.

Suzuki, Japan's No. 4 automaker, said 2.1 million vehicles were affected but Chief Executive Osamu Suzuki told reporters his workers did not intentionally use improper data, reports Reuters. At least 16 models of Suzuki sold in Japan are under the scanner, include globally known models such as the Alto, WagonR, Swift, Jimney, Baleno, Ignis and the SX4 S-Cross. The company also said a proper testing subsequently had shown the mileage data did not need amending.

Mitsubishi Motors Corporation had admitted in April it had cheated on fuel efficiency tests to show better fuel consumption rates in over 600,000 vehicles. Mitsubishi confessed that the misconduct involved four mini-car models — the eK Wagon and eK Space manufactured and sold by MMC, and the Dayz and Dayz Roox manufactured by MMC for Nissan. Following the revelation, Nissan Motor Co Ltd announced a strategic alliance with Mitsubishi by acquiring 34 percent equity stake in it.

Nissan's U.K.-built Qashqais was accused of emission cheating by South Korea this month. However, the company has denied the allegations. Volkswagen had admitted in September last year that it fitted a "cheat device" in some of its diesel models sold in the United States to pass government emissions tests. Latest reports say Volkswagen is planning to offer buyback of up to 500,000 units of diesel cars in the U.S., which have been affected by the "Dieselgate" scandal.