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.