Method and apparatus for a control system of an automatic transmission

A method and apparatus control an automatic transmission (3). A controller prohibits (S14) a down-shift of the automatic transmission (3) when the input rotation speed of the automatic transmission (3) is determined to be equal to or greater than a predetermined value due to operating characteristics of a device or a plurality of devices installed in a vehicle equipped with the automatic transmission (3) and an engine (2). Since the down-shift of the automatic transmission (3) is prohibited (S14), when the input rotation speed is determined to be equal to or greater than the predetermined value, the input rotation speed of the automatic transmission (3) is prevented from being further increased. Consequently, overrun of the engine (2) is effectively avoided.