Seoul said it would order recalls of hundreds of Qashqai model SUVs after tests revealed an emission defeat system that made the vehicle appear to be less polluting than it really was.
The decision follows an investigation into 20 diesel-powered cars last December, initiated by Seoul after German carmaker Volkswagen admitted to having installed devices aimed at cheating emissions tests into 11 million diesel engines.
"Our investigation... Concluded that Nissan illegally manipulated emission data," the ministry said in a statement.
Hong Dong-Kon, a ministry official handling transport-related regulations, added: "A group of auto industry experts we consulted with also agreed that this is a clear manipulation of emission data."
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State tests showed the Qashqai switched off its emission reduction device when the car temperature reached 35 degrees Celsius to stop the vehicle from overheating, whereas other cars waited until the temperature reached 50 degrees.
The ministry also said that when the Qashqai's emissions reduction device stopped working, the level of emissions was about the same or higher than the Volkswagen's cars equipped with emissions-cheating software systems.
Mitsubishi last month admitted it had been falsifying fuel-economy tests for years, manipulating data to make cars seem more efficient than they were in reality.
The scandal includes mini-cars produced by Mitsubishi for Nissan as part of a joint venture, but Nissan is said to have had no part in the cheating.
Nissan threw a surprise lifeline to Mitsubishi last week by offering to buy 34 per cent of its shares, but its top executive warned Friday that he would kill the USD 2.2 billion offer if the Mitsubishi scandal spreads beyond Japan.