Patent ID: 7104907

Claim:
A system for controlling an automatic transmission, comprising: a source of a line pressure; an oil-temperature sensor which senses a temperature of a transmission oil; an engine-speed sensor which senses an engine speed; a hydraulic-pressure sensing device which senses an actual value of the line pressure; a control circuit which controls the line pressure; and a control unit which controls the control circuit, the control unit being configured to: determine that engine cranking starts when the engine speed is greater than a predetermined speed; set as a low-pressure control set time a time required from start of engine cranking to completion of an overshoot of the line pressure due to increase in the engine speed; determine that the actual value of the line pressure is equal to or greater than a predetermined value; determine that the actual value as determined is held for a period longer than the low-pressure control set time; and provide first and second indicated values of the line pressure to the control circuit when the transmission-oil temperature at engine start is equal to or smaller than a predetermined temperature, the first indicated value being smaller than the second indicated value, the first indicated value being provided when at least a range other than a drive range is selected, the second indicated value being provided when the drive range is selected, the second indicated value being provided when it is determined that the actual value of the line pressure is equal to or greater than the predetermined value, and when it is determined that the actual value as determined is held for the period longer than the low-pressure control set time.