| 摘要 |
PURPOSE: A method for diagnosing a defect of a thermostat is provided to exactly decide a mechanical trouble of the thermostat by correction for the traveling wind and to improve diagnosis performance by expanding a decision condition. CONSTITUTION: A method for diagnosing a defect of a thermostat is composed of steps for deciding if satisfying a thermostat-defect diagnosing execution condition with accumulating the traveling speed as an engine starts(S100,S110,S120); setting up a decision initial set time according to the intake amount of air and subtracting the initial set time to 0 time point(S130); re-setting and subtracting a defect decision time of the thermostat to the 0 time point as the intake amount of the air is changed during subtracting the decision initial set time(S160); storing the temperature of coolant and computing an average of the accumulated vehicle speed if the subtracted defect decision time of the thermostat reaches the 0 time point(S190,S200,S210); calculating a basic decision temperature correction value for the temperature of coolant according to affection of the traveling wind for an average value of the computed vehicle speed; and deciding if the thermostat is broken down by comparing the coolant temperature-basic decision temperature correction value with an actual coolant temperature according to the calculated traveling wind.
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