Patent ID: 7934418

Claim:
An abnormality diagnosis device of an intake air quantity sensor for sensing an intake air quantity of an internal combustion engine, the abnormality diagnosis device comprising: an abnormality diagnosing means for performing abnormality diagnosis of the intake air quantity sensor; a power supply switching means for temporarily powering off the intake air quantity sensor and then powering on the intake air quantity sensor again during an operation of the internal combustion engine; and a steady operation determining means for determining whether an operation state of the internal combustion engine is a steady operation state, wherein the abnormality diagnosing means temporarily powers off the intake air quantity sensor and then powers on the intake air quantity sensor again with the power supply switching means in a period in which the steady operation determining means determines that the operation state of the internal combustion engine is the steady operation state, and the abnormality diagnosing means senses an output rising characteristic of the intake air quantity sensor at the time when the intake air quantity sensor is powered on again and performs the abnormality diagnosis of the intake air quantity sensor based on a sensing value of the output rising characteristic.