The institute, which is controlled by the South Korean government, said it will also check differences in cars' performances before and after the exhaust gas recirculation module was replaced.

BMW has blamed the exhaust gas recirculation component as the "root cause" of recent fires. The EGR is one of the principal devices used to reduce nitrogen oxide emissions from diesel engines.

The institute has asked the German carmaker to submit relevant documents to compare any possible differences in the EGR modules in 520d sedans in South Korea and Europe, adding it is seeking to secure a BMW car equipped with a European engine.

Plans for extensive tests come amid lingering public concerns in South Korea about the safety of the German vehicles.

BMW's South Korean unit has begun recalling more than 106,000 BMW cars.

Over 40 fires in BMW cars have been reported so far this year, though there have been no injuries or fatalities.

South Korea has formed a joint investigation team -- composed of 20 outside experts and 14 inside experts -- in a move to ensure that tests are carried out in a thorough and transparent manner.

Earlier this week, about 1,000 consumers in South Korea asked the United States and Germany to open an investigation into BMW over its alleged concealment of defects in its cars. (Yonhap)