Failure detection device for exhaust gas recirculation device

A failure detection device for an exhaust gas recirculation device, the exhaust gas recirculation device comprising:

• an exhaust gas recirculation passage through which an exhaust passage and an intake passage of an engine communicate with each other, and
• an exhaust gas recirculation valve disposed in the exhaust gas recirculation passage, wherein the failure detection device comprises:
• a failure type estimation unit for estimating a type of failure that has occurred in the exhaust gas recirculation device;
• and
• a determination unit for determining presence or absence of a failure from an intake air pressure change when opening degree of the exhaust gas recirculation valve is changed during a fuel cut operation, and
• wherein the determination unit is configured to determine the presence or absence of a failure by changing the opening degree of the exhaust gas recirculation valve in accordance with the type of failure estimated by the failure type estimation unit during failure diagnosis.