ABNORMALITY DETERMINATION APPARATUS AND ABNORMALITY DETERMINATION METHOD FOR COOLANT TEMPERATURE SENSOR, AND ENGINE COOLING SYSTEM

摘要

A coolant temperature sensor abnormality determination apparatus opens a changeover valve (10) to increase the temperature of a coolant in a heater passageway (202) if the amount of increase of the detected heater inlet coolant temperature value thw2 obtained when the intake air amount of an engine (1) becomes equal to or greater than a predetermined value is small. Then, if the amount of increase (thw2 deviation) in the detected heater inlet coolant temperature value thw2 after the changeover valve (10) opens is greater than or equal to the predetermined value, the apparatus determines that the heater inlet coolant temperature sensor (22) is normal. If the amount of increase in the detected heater inlet coolant temperature value thw2 is smaller than the predetermined value, the apparatus determines that the heater inlet coolant temperature sensor (22) is abnormal.