Abstract: A method for detecting an open load fault of a wideband lambda sensor of a motor vehicle. The wideband lambda sensor includes at least one heater. The method includes: a) enabling a fault check, wherein a temperature model is used to check if the wideband lambda sensor (112) is sufficiently heated; b) carrying out the fault check; if no fault is detected according to the fault check, the following step is carried out: b1) concluding the method with a result of OK; if a fault is detected according to the fault check, the following step is carried out: b2) concluding the method with a result of not OK; before step b) is carried out, the necessity of overheating protection is checked, and if the overheating protection is necessary, a heater voltage of the heater is reduced simultaneously with step a) or before step a) is carried out.

Abstract: A method of detecting a blocked pressure line in an internal combustion engine SCR system, which includes a feed pump, a dosing module, a pressure sensor, and an electronic control unit, includes a reference signal of a pressure (p) in the pressure line being measured over a measuring time (tM) if a reducing agent solution is not dosed by the dosing module, and a signal energy of the reference signal is then calculated; a pressure signal being measured over the measuring time (tM) during the dosing of a dosing mass of the reducing agent solution by the dosing module; and a signal energy of the pressure signal is then calculated; a ratio of the signal energies of the pressure signal to the signal energy of the reference signal being calculated; and finally the blocked pressure line being detected if the ratio falls short of a first pre-definable threshold value.

Abstract: The invention relates to a method for detecting a blocked pressure line in an SCR system of an internal combustion engine. The SCR system comprises a feed pump, a dosing module and a pressure sensor. The method comprises the following steps: a reference signal of a pressure (p) in the pressure line is measured over a measuring time (tM) if a reducing agent solution is not dosed by the dosing module, and a signal energy of the reference signal is then calculated. A pressure signal is measured over the measuring time (tM) during the dosing of a dosing mass of the reducing agent solution by the dosing module, and a signal energy of the pressure signal is then calculated. Finally, a ratio of the signal energies of the pressure signal to the signal energy of the reference signal is calculated. The blocked pressure line is detected if the ratio falls short of a first pre-definable threshold value.

Abstract: A method for determining an exhaust gas temperature of an internal combustion engine, which is performed by measuring a lambda value of the exhaust gas of the internal combustion engine and calculating a calculated exhaust gas temperature as a function of the measured lambda value, and comparing the calculated exhaust gas temperature with a measured exhaust gas temperature and adapting a function used for the calculation as a function of the comparison.

Abstract: A method for determining an exhaust gas temperature of an internal combustion engine, which is performed by measuring a lambda value of the exhaust gas of the internal combustion engine and calculating a calculated exhaust gas temperature as a function of the measured lambda value, and comparing the calculated exhaust gas temperature with a measured exhaust gas temperature and adapting a function used for the calculation as a function of the comparison.