| 摘要 |
PROBLEM TO BE SOLVED: To surely and rapidly carry out fault diagnosis for an item to be diagnosed in an engine using an electronic throttle control system, by surly continuing diagnosing terms in accordance with an engine condition. SOLUTION: Diagnosing terms are determined in accordance with an operating condition of an engine, and if the diagnosing terms are satisfied, fault diagnosis is carried out for an item to be diagnosed. Further, a desired throttle opening degree THVTGT for a throttle valve is set with reference to a table in accordance with an accelerator opening degree ALPH indicating a degree of manipulation upon an accelerator by a driver (S21). Further, the fault diagnosis is carried out (S22), and when the fault diagnosis is not carried out, the above-mentioned desired throttle opening degree THVTGT which has been set in accordance with the accelerator opening degree ALPH is used. Meanwhile, during execution of the fault diagnosis, a desired throttle opening degree THVTGT is reset in accordance with an actual throttle opening degree THVDIAGST upon initiation of the fault diagnosis (S24). Further, a control value DACT for a throttle valve actuator for actuating the throttle valve is set in accordance with a deviationΔTH between the desired throttle opening degree THVTGT and a present actual opening degree of the throttle valve (S25 to S27).
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