A method for a two-point lambda sensor includes, changing a composition of an air/fuel mixture supplied to an internal combustion engine from a predefined lambda value to lambda=1, determining a delay time of the voltage value reaching a value corresponding to the lambda=1, again changing the composition of the air/fuel mixture from the predefined lambda value to lambda=1, determining a characteristic of the changing performed in the second regulation based on the delay time, determining an actual value of lambda on an actual voltage-lambda characteristic curve of the two-point lambda sensor that corresponds to the predefined lambda value which is in reference to a reference voltage-lambda characteristic curve based on the determined characteristic, and identifying a voltage offset between the characteristic curves based on a deviation of the actual value from the predefined value.