PURPOSE: To have fail-safe control by sensing any failure on an oil temp. sensing system on the basis of information from an engine water temp. sensor and an oil temp. sensor, and thereby avoiding line pressure up control at the time with low temp. while the oil temp. sensing system is in erroneous operation.
CONSTITUTION: In the condition in which the engine water temp. has risen sufficiently, i.e. in case where a signal about below -30°C for ex. is fed a prescribed time after a signal about high temp. at the engine is given from an engine water temp. sensor 4, an oil temp. sensor 3 system judges a bad operating condition, i.e. trouble of the oil temp. sensor 3 itself or severance in the wiring of the sensor 3, and low temp. control is stopped to be replaced with normal temp. control. In this manner a bad operating condition of the oil temp. sensor 3 system is sensed by the co-use of an engine water temp. sensor 4, and on the basis thereof the fail-safe control of oil temp. sensor 3, for ex. line pressure up control to be implemented at the time of low temps., can be prohibited.
SUZUKI KENJI
MINOUE KAZUHIRO
