Method and apparatus for the self-diagnosis of an exhaust gas probe

A method for the self-diagnosis of an exhaust gas probe (20), the exhaust gas probe (20) having at least one heating element (26), characterized in that a modeled parameter is determined for the heating element (26) by means of a computer program comparing parameters of the gas stream with the modeled parameter, and determining, when the parameters of the gas stream exceeds the modeled parameter 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.

An apparatus for the self-diagnosis of an exhaust gas probe (20), the exhaust gas probe (20) having at least one heating element (26) and the exhaust gas probe (20) being connected to a controller, and the controller having devices for the diagnosis of the exhaust gas probe (20), characterized in that the controller has at least one calculating unit for the determination, in a modeled manner, of a parameter which denotes the correct operation of the exhaust gas probe (20), this parameter determined from parameters of the gas stream, and comparing said parameter with a measured parameter by means of at least one evaluation unit which is integrated into the controller, and determining the exhaust gas probe (20) is defective when a deviation exceeds a defined tolerance limit, or determining a faulty condition exists in an exhaust gas section (17), in which the exhaust gas probe (20) is installed.