Stuttgart prosecutors said they had opened the probe based on the findings of a United Nations report last month that named the carmaker as one of thousands of companies which paid bribes to Saddam Hussein's government.
At issue is whether the sale of a truck to Iraq violated German laws restricting exports.
"There is suspicion that approval for the export was obtained by fraud because a special payment of 13,589.50 marks was not declared," the prosecutors said in a statement.
The UN report cited a payment worth $7,134. DaimlerChrysler has said in the past it was co-operating with investigations of the oil-for-food programme but has declined further comment.
The programme, which ran from 1996 to 2003, aimed to ease the impact on Iraqis of UN sanctions imposed in 1990 after Baghdad's troops invaded Kuwait. It allowed Iraq to sell oil to pay for food, medicine and other goods.
The UN survey said more than half the firms doing business with Iraq wittingly or unwittingly fed Saddam's need for cash through straight bribes or surcharges on oil sales.