An exhaust gas aftertreatment system and method are provided. The system comprises a controller, a pump, and a volume quantity dispensing unit. The volume quantity dispensing unit comprises a pressure transducer comprising an electric pressure sensor, at least one fine atomizing nozzle for apportioning the aqueous solution directly into an exhaust gas flow, and at least one means for changing a pressure value. The means changes the pressure value in such a way that a pressure output signal from the pressure transducer to the controller is modified from an actual pressure value sensed by the pressure sensor. A first signal provided by the controller to the pump and a second signal provided by the controller to the volume quantity dispensing unit are adapted based on the output signal from the pressure transducer and a further signal indicative of an operating state of the internal combustion engine.