Patent ID: 7448202

Claim:
A diagnosis apparatus for a secondary air supply system for an internal combustion engine, the secondary air supply system comprising: at least one secondary air supply passage, through which secondary air is supplied to an upstream of an exhaust gas purification apparatus in at least one exhaust passage of the internal combustion engine; at least one valve for communicating the secondary air supply passage to be in an open condition and for blocking the secondary air supply passage to be in a close condition; and a detecting unit for detecting a detection object of secondary air in an upstream of the valve in the secondary air supply passage, the diagnosis apparatus comprising: a diagnosis unit for obtaining a detection result of the detecting unit in each of the open condition of the least one valve and the close condition of the least one valve, the diagnosis unit being adapted to evaluating an abnormity of the secondary air supply system in accordance with the detection result; a reliability maintaining unit for determining the diagnosis operation of the diagnosis unit to be valid when the detecting operation of the detecting unit in the open condition and the detecting operation of the detecting unit in the close condition are continuously performed; and an evaluating unit for evaluating whether an executing condition is satisfied for permitting the diagnosis operation, wherein the diagnosis unit performs the diagnosis operation when the evaluating unit determines the executing condition to be satisfied, and the reliability maintaining unit determines an operation related to the diagnosis operation of the diagnosis unit to be invalid when the evaluating unit determines that the executing condition is not satisfied while the diagnosis unit performs the operation related to the diagnosis operation of the diagnosis unit.