Gas sensor system

A gas sensor system comprising:

• a gas sensor having an oxygen pump cell electrically communicating with a first terminal and a second terminal, and an oxygen concentration detection cell communicating with the second terminal and a third terminal;
• and
• a sensor control section which includes a first terminal potential detection circuit for detecting a first terminal potential of the first terminal, a second terminal potential detection circuit for detecting a second terminal potential of the second terminal, and a third terminal potential detection circuit for detecting a third terminal potential of the third terminal and which controls the gas sensor through the first terminal, the second terminal, and the third terminal, wherein
• the sensor control section includes:
• an examination potential circuit for applying to the second terminal a predetermined examination potential which is higher than a ground potential and is lower than a power supply potential of a power supply for control of the sensor control section;
• a first circuit for disconnectably connecting the first terminal and the second terminal, the first circuit having a resistance which is lower than an input resistance of the first terminal potential detection circuit, is lower than an internal resistance of the oxygen pump cell in a state in which the oxygen pump cell does not exhibit oxygen ion conductivity, and is higher than the internal resistance of the oxygen pump cell in a state in which the gas sensor is an activated state;
• a second circuit for disconnectably connecting the second terminal and the third terminal, the second circuit having a resistance which is lower than an input resistance of the third terminal potential detection circuit, is lower than an internal resistance of the oxygen concentration detection cell in a state in which the oxygen concentration detection cell does not exhibit oxygen ion conductivity, and is higher than the internal resistance of the oxygen concentration detection cell in a state in which the gas sensor is in the activated state;
• and
• terminal potential detection means for detecting the first terminal potential, the second terminal potential, and the third terminal potential using the first terminal potential detection circuit, the second terminal potential detection circuit, and the third terminal potential detection circuit in a state in which the examination potential is applied to the second terminal, and in a state in which the first circuit and the second circuit are connected.