Abstract: A sensor-failure decision system for determining a sensor failure of an automobile temperature sensor, comprises a first memory section adapted to receive input information indicative of a temperature of working fluid used in the automotive power train component part and detected by the automobile temperature sensor, a second memory section for storing a predetermined normal temperature region and a plurality of predetermined partitioned temperature regions which are obtained by partitioning a specified temperature region being lower than and continuous with the predetermined normal temperature region into a plurality of temperature regions, and a timer for measuring an elapsed time during which the temperature detected by the automobile temperature sensor is continually included in either one of the partitioned temperature regions.

Abstract: An apparatus for checking a trouble in a communication circuit connected between engine and transmission control units. A check signal is produced at uniform intervals of time. The check signal is converted into a predetermined code. The converted code is transmitted through the communication circuit from one of the engine and transmission control units to the other control unit. The code transmitted to the other control unit is monitored to produce a failure signal to indicate that a trouble occurs in the communication circuit when the monitored code is not identical with the predetermined code.