FAILURE DETERMINATION DEVICE OF EXHAUST GAS SENSOR

PROBLEM TO BE SOLVED: To provide a failure determination device for sensing clogging of an exhaust gas inlet port for introducing exhaust gas into a detection portion of an exhaust gas sensor, and determining the failure of the exhaust gas sensor caused by the clogging of the exhaust gas inlet port.SOLUTION: The failure determination device 2 of a PM sensor 9 having a sensor element 7 arranged in an exhaust gas system of an engine 1 to detect the state of exhaust gas of the engine 1, and a cavity 13 for introducing a part of the exhaust gas into the sensor element 7 includes a heater for raising the temperature of the sensor element 7, a parameter detection portion 5 for detecting a parameter correlated with the influence from the exhaust gas to the sensor element 7 after raising the temperature of the sensor element 7 to a predetermined temperature higher than an exhaust gas temperature by the heater, and a failure determination portion 5 for determining the failure of the PM sensor 9 caused by the clogging of the cavity 13 based on the parameter detected by the parameter detection portion 5.