PURPOSE: To easily diagnose a trouble in a switch, by diagnosing the trouble of short circuit or breaking caused in the switch, which provides two operating points restricting the actuating range of a throttle valve driving step motor, on the basis of a result comparing a number of steps, when the operatng point is switched, with several kinds of preset values.
CONSTITUTION: The opening of a throttle valve 43 interposed in an intake pipe 44 is controlled by a step motor 51 driven relating to the control amount of an accelerator pedal 16, and the throttle valve 43 is normally set to an idle position by urging with a spring 53 an actuating lever 52 fixed to a valve shaft 42. A switch having operating points S1, S2 for detecting the idle position and full opening position of the throttle valve 43 is provided in a moving route of said actuating lever 52. Then a trouble in the switch is diagnosed on the basis of an acting condition of the switch between the first, fourth preset values and the second, third preset values by providing the first and the third values preset smaller and similarly the second and the fourth values preset larger by a predetermined number than the number of steps when the operating points S1 and S2 are switched.
SHISHIDO KAZUYA
KASAI HITOSHI
MORIIDE SHIGEKI
FUJITSU LTD
| JPS5828572A | 1983-02-19 | |||
| JPS51121657A | 1976-10-25 | |||
| JPS53104804A | 1978-09-12 |