A method and a corresponding system for error checking an electrochemical sensor having at least two electrodes and a liquid measuring medium applied thereto are disclosed. The method involves determining a first admittance between a first set of electrodes of the sensor; determining a second admittance between a second set of electrodes of the sensor; determining a value using the first admittance and the second admittance; and displaying an error message if the value is out of a predetermined tolerance.