Method for controlling the operation of an exhaust aftertreatment system

A method for controlling the operation of an exhaust aftertreatment system (EATS) in a vehicle is described. The EATS comprises a main SCR catalyst and a pre-SCR catalyst, a pre-injector arranged upstream the pre-SCR catalyst for providing reductant, a bypass channel fluidly connected to the fluid channel and arranged to bypass the pre-SCR-catalyst and the pre-injector, and a valve configured to control a split of exhaust gases between the pre-SCR catalyst and the bypass channel. The method includes determining the amount of ammonia stored in the pre-SCR catalyst; determining the temperature of the main SCR catalyst; when the ammonia storage in the pre-SCR catalyst is below an ammonia storage threshold and the temperature of the main SCR catalyst is above a temperature threshold, injecting reductant by the pre-injector and controlling the valve to allow a flow of exhaust gases to the pre-SCR catalyst sufficient for transporting the injected reductant to the pre-SCR catalyst for increasing the ammonia storage.