Patent ID: 8650942

Claim:
A method for diagnosing an exhaust gas sensor which is situated in an exhaust gas area of an internal combustion engine for detecting at least one exhaust gas component, which is heated using a sensor heater and whose sensor temperature is detected, the method comprising: heating the exhaust gas sensor to a diagnosis starting temperature which is higher than an exhaust gas temperature; at least one of: i) reducing heat output of the sensor heater and ii) completely turning off the sensor heater, such that a temperature of the sensor is able to decrease; detecting a drop of the temperature of the sensor; ascertaining a measure for the drop of the temperature of the sensor in relation to time; comparing the measure with a first temperature gradient threshold value; and providing an error signal if the ascertained measure for the drop of the temperature of the sensor in relation to time does not exceed the first temperature gradient threshold value.