German carmaker Daimler, which owns Mercedes-Benz, has said it will conduct an investigation into its exhaust emissions certification process in the US, following a request from the Department of Justice.
In a statement, Daimler said it “is cooperating fully with the authorities”.
It added: “Daimler will consequently investigate possible indications of irregularities and of course take all necessary actions.”
It comes as Volkswagen concluded a deal with US authorities over its emissions scandal, which will see it will offer compensation and buy back some cars.
The news of Daimler’s internal probe in the US follows Q1 results at the German carmaker showing its bottom-line profit slumped in the first three months of this year due to falling sales of two of its main model ranges.
Net profit fell by 31% to €1.353bn in the period from January, "impacted primarily by a life cycle-related decrease in unit sales of the S- and E-Class at the Mercedes-Benz Cars division," the company said.
Underlying or operating profit was down 26% at €2.148bn, while sales edged up 2% to €35.047bn in the three-month period.
Unit sales rose by 7% to 683,885 vehicles.
"Daimler is on a successful path. Our growth in unit sales clearly shows that we are following the right strategy and have the right products in the market," said chief executive Dieter Zetsche.
"The model offensive is continuing at the same speed. We will continually improve as the year progresses and will make 2016 into another successful year for Daimler," Mr Zetsche said.
