Abnormality-detecting device for exhaust gas component concentration sensor of internal combustion engine

In an abnormality-detecting device for an exhaust gas component concentration sensor of an internal combustion engine, said engine having an exhaust system in which is arranged said exhaust gas component concentration sensor for detecting concentration of a component of exhaust gases emitted from said engine, said abnormality-detecting device including abnormality-detecting means for detecting abnormality of said exhaust gas component concentration sensor, based on an amount of change in an output from said exhaust gas component concentration sensor exhibited when a predetermined voltage is applied thereto,

• the improvement wherein said abnormality-detecting means comprises normality-determining means for determining that said exhaust gas component concentration sensor is functioning normally when said amount of change in said output from said exhaust gas component concentration sensor exceeds a predetermined value, and abnormality determination-deferring means for deferring determination of abnormality of said exhaust gas component concentration sensor based on said amount of change in said output from said exhaust gas component concentration sensor, when said amount of change in said output assumes a value below said predetermined value before said engine reaches a predetermined operating condition after said engine is started.