Patent ID: 8513961

Claim:
A defect detection method for a sensor comprising a sensor element which includes at least one cell having a solid electrolyte layer extending in an axial direction; a tubular metallic member which surrounds the circumference of the sensor element; and a fixing member which is in contact with an inner surface of the tubular metallic member and an outer surface of the sensor element and provides a seal therebetween, the cell including a pair of conductors which are formed on the solid electrolyte layer such that the conductors extend through a portion of the sensor element surrounded by the fixing member, the method comprising the steps of: heating the tubular metallic member so as to produce a difference in dimension attributable to a difference in rate of thermal expansion between the tubular metallic member and the fixing member and a difference in rate of thermal expansion between the tubular metallic member and the sensor element; and detecting breakage of a portion of the pair of conductors surrounded by the fixing member in a state where the difference in dimension is present.