A method for operating a motor vehicle having an exhaust gas aftertreatment device involves an on-board electronic computing device receiving consumption information characterizing consumption of a reducing agent by the exhaust gas aftertreatment device and tank information characterizing a filling level of a reducing agent tank. Tank information is evaluated together with the consumption information with regard to a divergence, and upon determination of the divergence between the tank information and the consumption information, error information is stored in a blockchain characterizing the motor vehicle, and an action of the motor vehicle is triggered.