Method and device for diagnosing electrodes in sensor elements

A device for detecting at least one fraction of a gas component of a gas in a measuring gas chamber, comprising:

• at least one sensor element, the sensor element including at least one first electrode, to which the gas may be applied, and at least one second electrode, wherein the first electrode and the second electrode are connected via at least one solid electrolyte;
• and
• at least one controller configured for diagnosing the sensor element, by performing the following:
• applying a diagnostic signal between the at least one first electrode and the at least one second electrode, wherein the diagnostic signal is varied according to a pattern that is predefined as a function of passage of a predefined amount of time after each of the applications of the diagnostic signal, so that, after each of a plurality of time intervals following a first application of the diagnostic signal, the diagnostic signal is modified to a respective value that is different than an initial value of the diagnostic signal at the first application;
• and
• detecting a response signal between the first electrode and the second electrode and that varies according to the value variations of the diagnostic signal.