A method for regulating a temperature in an exhaust stream in a motor vehicle through control of its driveline. The motor vehicle includes a driveline having a combustion engine connected to a gearbox via a clutch device. The gearbox has several discrete gears. The driveline includes an exhaust system configured for the removal of an exhaust stream from the combustion engine. The method steps are: obtaining one or several first parameters P1, wherein at least one of first parameters P1 is a first temperature difference between a first temperature T1 in the exhaust system and a reference temperature TRef; and controlling the gearbox, and thus controlling an operating point in the combustion engine, through downshift to a lower gear, and thus increasing engine speed and reducing a load on the combustion engine, if a value of the one or several first parameters P1 exceeds a first threshold, and an upshift to a higher gear, and thus reducing an engine speed and an increase of a load on the combustion engine, if a value for the one or several first parameters P1 is below a second threshold value. Further, a computer program, a computer program product, a system and a motor vehicle comprising such a system are disclosed.