The US Department of Justice is to launch a criminal investigation into the Ford Motor Company.
The car-maker has said it relates to "potential concern" involving its emissions certification process in the US.
The firm added that it voluntarily disclosed this to the US Environmental Protection Agency (EPA) and the California Air Resources Board.
It made these disclosures back on February 18th and 21st, respectively.
In a regulatory filing, Ford said: "This matter currently focuses on issues relating to road load estimations, including analytical modeling and coastdown testing.
"The potential concern does not involve the use of defeat devices."
"Subsequently, the US Department of Justice opened a criminal investigation into the matter.
"In addition, we have notified a number of other state and federal agencies.
"We are fully cooperating with all government agencies.
"Because this matter is still in the preliminary stages, we cannot predict the outcome, and we cannot provide assurance that it will not have a material adverse effect on us."
Henry Ford first introduced the Model T in 1908, which signalled a new era in personal transport.
In Europe, Ford employs 53,000 employees at wholly-owned facilities and 68,000 people when joint ventures and unconsolidated businesses are included.
In 2018, nearly 1.1 million vehicles were produced at Ford's European facilities.
Ford of Europe is responsible for producing, selling and servicing Ford brand vehicles in 50 markets headquartered in Cologne, Germany.