FAILURE DETERMINATION DEVICE FOR AIR WEIGHT FLOW RATE DETECTOR, AND METHOD THEREOF

A failure determination device for an air weight flow rate detector that maintains the calculation accuracy for an estimated air weight flow rate value to be compared with a detection value from the air weight flow rate detector, thereby allowing the failure determination accuracy to be improved. A failure determination device (1) for an air weight flow rate detector (22) calculates the estimated air weight flow rate value GAIREST according to a relationship of the pressure in an air-intake passage (5) between an upstream side and a downstream side of an air weight flow control mechanism (7), and determines a failure in the air weight flow rate detector in accordance with a comparison result of the estimated air weight flow rate value GAIREST calculated in such a way and the detection value GAIR for the air weight flow rate detected by the air weight flow rate detector. Further, the failure determination device (1) detects an open degree parameter representing the open degree of the air-intake passage (5), while prohibiting failure determination for the air weight flow rate detector by the use of a failure determination means when the open degree of the air-intake passage (5) that is represented by the detected open degree parameter exceeds a given value.