The Ministry of Land, Infrastructure and Transport has found a correlation between emissions and fuel efficiency in Volkswagen's Tiguan vehicles run on diesel.
 
The ministry said Thursday that it analyzed Tiguan's emissions and fuel efficiency after receiving data from the Ministry of Environment.
 
The results showed that installing an emission reduction device affects a vehicle's fuel efficiency.
 
Experts believe activating the device uses up more fuel than when it is turned off.
 
The transport ministry plans to gauge the fuel efficiency of four Volkswagen models, including the Tiguan and the Passat, in a test lab as well as on the road at the beginning of next year.
 
The analysis of the four models will be inferred and applied to all vehicles carrying the same old-generation engines.