Patent ID: 7713391

Claim:
An apparatus for diagnosing an abnormality of a gas-concentration measuring apparatus, the gas-concentration measuring apparatus comprising: a gas sensor comprising a sensor device for outputting a signal commensurate with a concentration of a predetermined gas in a sample gas space, the sensor device comprising a solid electrolyte and a pair of electrodes provided on the solid electrolyte, and a heating section for heating the sensor device up to an activation temperature at which to output a signal commensurate with a concentration of the predetermined gas, the heating section being externally supplied with power; and a measuring section for measuring a concentration of the predetermined gas in the sample gas space based on an output signal of the sensor device, the measuring section being electrically connected by a plurality of electrically connecting lines to the electrodes of the sensor device of the gas sensor, the apparatus for diagnosing an abnormality of a gas-concentration measuring apparatus comprising: a determining section for determining whether or not voltages, on connection points between the measuring section and the sensor device, are a preset abnormal voltage value; a power-delivery control section for restraining a delivery of power to the heating section when a voltage, on any of the connection points, is determined as an abnormal voltage value by the determining section; and an abnormality diagnosing section for diagnosing an abnormality of any of the sensor device and the plurality of electrically connecting lines electrically connecting the measuring section to the electrodes of the sensor device after and while restraining a delivery of power by the power-delivery control section.