Patent ID: 6283381
Filing Date: 2001-09-04
Classification: F01P,F02D,G01K,G05B,Y02T

Abstract:
A diagnostic apparatus of a coolant temperature sensor sending out an output in correspondence to a temperature of a coolant of an engine, comprising:a setting section setting, as a measuring timing, a time when a predetermined time is elapsed after the engine started or a time when a predetermined heat is generated;a calculating section calculating a variation amount of the output of the coolant temperature sensor from a start of the engine to the measuring timing; anda judging section judging that a trouble occurs in the coolant temperature sensor when the variation amount is smaller than a predetermined value,wherein the variation amount of the output of the coolant temperature sensor is a difference between a maximum value of the output from the start of the engine to the measuring timing and a minimum value of the output from the start of the engine to the measuring timing.