Patent ID: 7010908

Claim:
An anomaly judgment apparatus for a secondary air supply system which includes a secondary air supply path for introducing secondary air into a portion of an exhaust path of an internal combustion engine located upstream of a catalytic converter disposed in the exhaust path, and an open-close valve which utilizes, as negative pressure, pressure in a portion of an intake path of the engine downstream of a throttle valve disposed in the intake path, the open-close valve being at least one of opened and closed by means of drive force produced by the negative pressure so as to open and close the secondary air supply path, the anomaly judgment apparatus comprising: anomaly judgment means for judging whether or not the secondary air supply system is anomalous; negative pressure judgment means for judging whether or not the negative pressure is secured to a degree required for the drive force to at least one of reliably open and close the open-close valve; and anomaly judgment prohibition means for prohibiting judgment by the anomaly judgment means when the negative pressure judgment means judges that the negative pressure is not secured to the required degree.