SHIFT STAGE SELECTION ABNORMALITY DETECTING DEVICE OF AUTOMATIC TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To detect abnormality even at selection abnormality coourrence time of an abnormality detecting object shift stage by mechanical trouble by judging selection abnormality of a shift stage when detecting a selecting state of the abnormality detecting object shift stage even in case of no command of the abnormality detecting object shift stage to an electronic control valve from a controller. SOLUTION: Even in the case of no command of an M range first speed to a shift solenoid A from a controller 14, when causing a mismatching state of turning on an A solenoid pressure switch 13 due to generating M range first speed selecting A solenoid pressure imparting a large sense of incompatibility to a driver at abnormality selecting time, in case of checking whether it is at 4→2 speed change time or a second speed or third speed steady state, and ON directional trouble of the shift solenoid A is judged when a mismatching state continuous for a preset time or more. Both shift solenoids A, B are turned off, an automatic transmission is inputted to a third speed capable of self- traveling at an untroubled vehicle speed, and an alarm 12 is turned on the inform a driver of abnormality.