Failure determination system and method for temperature sensors, as well as engine control unit

摘要

A failure determination system for determining failures of temperature sensors, which is capable of easily and accurately determining failures of the sensors in actual operating temperature ranges thereof, even when the ranges are different from each other. Temperatures detected by exhaust gas temperature sensors are stored as initial temperatures when the engine has stopped. Temperatures detected by the respective sensors after stoppage of the engine are made dimensionless based on the corresponding initial temperatures to thereby calculate dimensionless values. An estimated dimensionless value of a temperature to be detected when each sensor is normal is set in advance as an estimated normal value. Failures of the sensors are determined based on results of comparisons of the dimensionless values with the estimated normal value.