Control device for an automatic transmission

摘要

A control device for an automatic transmission comprising a pressure regulator valve for regulating an engaging pressure acting on a friction engagement device for setting a speed change gear of an automatic transmission, a signal pressure output valve for outputting a signal pressure and a selector valve. The device further comprises a selector valve for selectively applying a signal pressure for setting a pressure regulation level to the pressure regulator valve and another control valve, abnormality detecting means for detecting both abnormal pressure regulation of the engaging pressure of the friction engagement device in speed changing to a speed change gear set by the friction engagement device that is brought into engagement when a regulated oil pressure is supplied and an abnormal operation based on the supply of the signal pressure to the control valve, and speed change gear prohibiting means for prohibiting the speed change gear when the abnormality detecting means detects at least either of the abnormal pressure regulation and abnormal operation.