Abstract: A procedure and device for diagnosing the increasing speed and the dead time of an exhaust gas probe includes carrying out the diagnosis by comparing a modeled and a measured signal after a default change of a fuel air ratio of an air fuel mixture that is supplied to a combustion engine. The signal is an output signal of the exhaust gas probe or a modeled or measured signal that is derived from the output signal. The device for diagnosing the velocity and the dead time of an exhaust gas probe also includes a comparing unit for comparing the modeled signal with the measured signal for diagnosing the velocity and the dead time of the exhaust gas probe after a default change of a fuel air ratio of an air fuel mixture that is supplied to the combustion engine.

Abstract: The invention concerns a procedure and a device for diagnosing the dynamic of an exhaust gas sensor, which is arranged in an exhaust gas duct of a combustion engine and with which a parameter of the gas mixture that is supplied to the combustion engine is regulated by a control loop. It is thereby provided according to the invention that during a diagnosing period a temporal deflection of a regulation correcting variable for the parameter that is derived from an output signal of the exhaust gas sensor or a temporal course of the output signal of the exhaust gas sensor is used for the diagnosis and that the dynamic of the exhaust gas sensor is assumed in an evaluation algorithm. Thereby an improvement of the on-board diagnosis of the dynamic of the exhaust gas sensor can be achieved and in particular lambda probes, which provide a slowing down of their responding behavior, can be detected early on.

Abstract: The invention relates to a procedure and a device for diagnosing the increasing speed and the dead time of an exhaust gas probe, which is arranged in the exhaust gas duct of a combustion engine, whereby the diagnosis is carried out due to a comparison of a modeled and a measured signal after a default change of a fuel air ratio of an air fuel mixture that is supplied to the combustion engine and whereby the signal is an output signal of the exhaust gas probe or a modeled or measured signal that is derived from the output signal.

Abstract: The invention concerns a procedure and a device for diagnosing the dynamic of an exhaust gas sensor, which is arranged in an exhaust gas duct of a combustion engine and with which a parameter of the gas mixture that is supplied to the combustion engine is regulated by a control loop. It is thereby provided according to the invention that during a diagnosing period a temporal deflection of a regulation correcting variable for the parameter that is derived from an output signal of the exhaust gas sensor or a temporal course of the output signal of the exhaust gas sensor is used for the diagnosis and that the dynamic of the exhaust gas sensor is assumed in an evaluation algorithm. Thereby an improvement of the on-board diagnosis of the dynamic of the exhaust gas sensor can be achieved and in particular lambda probes, which provide a slowing down of their responding behavior, can be detected early on.

Abstract: A circuit arrangement is proposed to diagnose a heating resistor, which is connected in series with a first switch, which connects the heating resistor to a power source for operation of the heating resistor with a heating current. Provision is made for means to operate the heating resistor with a diagnostic current during a cut-out time of the heating current and for means to acquire a diagnostic voltage as a measurement for the voltages occurring at the heating resistor as well as means to calculate the resistance of the heating resistor, which is taken as a basis for the diagnosis.