A method for the self-diagnosis of an exhaust gas probe (20). The exhaust gas probe (20) has at least one heating element (26). The method includes a modeled heat output PH is determined for the heating element (26) by means of a computer program comparing parameters of the gas stream with a measured heat output, and determining, when the parameters of the gas stream exceeds the measured heat output by more than a defined tolerance limit, that one of the exhaust gas probe (20) is defective, and an exhaust gas section (17) in which the exhaust gas probe (20) is installed is faulty.