Patent ID: 7434450

Claim:
An exhaust gas sensor defect detection apparatus, comprising: an exhaust gas sensor that outputs a sensor signal used for a control of an internal combustion engine; and a sensor-signal correction device that corrects a value of the sensor signal output from the exhaust gas sensor, wherein: a reverse voltage is applied to the exhaust gas sensor to determine whether a defect is present in the exhaust gas sensor; the sensor-signal correction device corrects the value of the sensor signal output from the exhaust gas sensor during a time period after application of the reverse voltage starts; the time period consists of a reverse-voltage application time period in which the reverse voltage is applied, and a return time period from when application of the reverse voltage ends until when the value of the sensor signal returns to a normal value; and the return time period is set to decrease as an the internal resistance of the exhaust gas sensor decreases.