The German automaker has formed a JV with Chinese SUV maker Great Wall Motor.
Rupert Stadler is being investigated on suspicion of fraud and indirect improprieties with documents.
Automaker ordered to recall over 6,000 Mercedes-Benz Vito delivery vans last week for emissions violations.
Governments scramble to save billions of dollars in trade after US re-imposes sanctions.
Issue is of particular concern for an economy that runs on exports of automobiles and machinery.
Further strikes are planned at BMW, Audi, Daimler and Porsche.
Coal power is responsible for more than 40% of global carbon dioxide emissions.
Prices are rising, making imports from sources in Europe and more attractive.
Drop follows a 1.2% rise in May.
Company said it has neither sought nor received assurances it would not be hit with border taxes when it ships parts to Britain.
Newsmagazine report claims the automakers have colluded for years over diesel technology.
Daimler claims it is “behaving in accordance with the law.”
Penalties to the three suppliers total $11 million.
Move is part of restructuring plans announced last fall to eliminate 7,500 transportation and aerospace jobs around the world.
Changes include capacity for cyber security, expansion of platforms for data analysis.