摘要 |
In a disclosed diagnostic apparatus and a diagnostic method of a coolant temperature sensor, a time point when a predetermined time is elapsed after an engine started or when a predetermined heat amount is generated in the engine after the engine started is set as a measuring timing. A variation amount of output of the coolant temperature sensor from the start of the engine to the measuring timing is calculated, and it is judged that a trouble occurs in the coolant temperature sensor when the variation amount is smaller than a predetermined value. The apparatus and the method are preferably applied to diagnosis of a cooling apparatus comprising a cooling section for carrying off heat of the engine by coolant to cool the engine, a radiator for radiating the heat carried off by the coolant, and a thermostat for controlling a flow rate of the coolant which circulates via the cooling section and the radiator.
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