A method for the regulation of 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, which may be connected to a gearbox via a clutch device, and an exhaust system for removing an exhaust stream from the engine. The method includes controlling the driveline for activation or deactivation of coasting of the vehicle based on one or several first parameters P1 and one or several second parameters P2 for regulation of a temperature TEx in the exhaust system. At least one of the first parameters P1 is a first temperature difference between the first temperature T1 in the exhaust system and a reference temperature TREF. The said second parameter P2 is related to a calculated speed and/or a calculated road inclination over the road section ahead for the motor vehicle. Further, a computer program, a computer program product, a system and a motor vehicle including such a system are disclosed.