In a method for operating a lambda sensor disposed in an exhaust gas system of an internal combustion engine,—the heating element is subjected to a predefined heating power substantially with the start of the engine;—during the heating process, the sensor signal is detected and compared to a threshold value specified for a lean and/or rich fuel/air mixture ratio, wherein the threshold value correlates with a sensor temperature, which is below the water ingestion critical temperature, and to a valid lambda signal,—when one of the specified threshold values is reached for the first time, a measured variable correlating with the sensor temperature is determined and the lambda signal is set as valid and forwarded, and—the determined measured variable correlating with the sensor temperature is transferred to a closed heating element control loop as a target value that corresponds to a target temperature.