Methods and systems are provided for an exhaust gas aftertreatment system for a combustion engine in a motor vehicle. In one example, the exhaust gas aftertreatment comprises at least two catalyst devices arranged in an exhaust tract, and a feed device for a reducing agent arranged between the two catalysts, and which furthermore comprises a first heat device at the inlet of the first catalyst and a second heat device downstream thereof, the system adapted for the reduction of nitrogen oxides.