Method for determining an electrical fault of a conductivity sensor, and conductivity sensor

A method for determining an electrical fault of a conductivity sensor for ascertaining the electrical conductivity of a medium, wherein the conductivity sensor comprises a first electrode pair and a second electrode pair both fully disposed in the medium, the method comprising:

• applying an electrical alternating voltage to the first electrode pair;
• measuring a temporal profile of the electrical alternating current at the first electrode pair resulting from application of the electrical alternating voltage at the first electrode pair;
• ascertaining a current-amplitude characteristic value from the temporal profile of the electrical alternating current;
• and
• if the current-amplitude characteristic value is below a first current threshold value or above a second current threshold value, identifying an electrical fault of the conductivity sensor identifying an electrical fault of the conductivity sensor;
• or
• if the current-amplitude characteristic value lies between the first current threshold value and the second current threshold value, measuring a temporal profile of the electrical alternating voltage at the second electrode pair resulting from application of the alternating voltage at the first electrode pair, determining a voltage-amplitude characteristic value of the temporal profile of the electrical alternating voltage at the second electrode pair, and determining an electrical fault of the second electrode pair if the ascertained voltage-amplitude characteristic value lies below a voltage threshold value.