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LINE PRESSURE CONTROL OPERATION

BHE051318901T08

• Line pressure switches to high or low pressure in accordance with line pressure switching pre-programmed in the TCM.

• If the pressure control solenoid valve is energized, line pressure switches to the low-pressure side; if the pressure control solenoid valve is de-energized, line pressure switches to the high-pressure side.

1 | Oil pressure
2 | Low pressure
3 | High pressure
4 | Solenoid on
5 | Solenoid off
6 | D range
7 | P, N, R position

• Line pressure generated by the oil pump (discharge pressure) acts on the area marked A on the pressure control valve. It, however, does not act if the pressure control valve is turned on by a signal relayed from the TCM. Thus line pressure is regulated to match the spring force acting on the right side of the pressure control valve. If the pressure control solenoid turns off, solenoid pressure acts and line pressure is regulated to match the spring force and solenoid pressure acting on the right side of the pressure control valve. As a result, line pressure is decreased when the pressure control solenoid valve is on, and increased when it is off.

• Line pressure, which acts only in D range, acts on the area marked B on the pressure control valve. Thus, the pressure control valve moves in the direction in which oil is drained, and line pressure is decreased by an amount equal to the surface area marked B.

1 | Line pressure
2 | Line pressure: acts only in d range
3 | To control valves (regulated)
4 | Drain
5 | Pressure control valve
6 | Spring
7 | Solenoid pressure
8 | Pressure control solenoid
9 | Lower passage opens when solenoid pressure acts
10 | Upper passage opens when solenoid pressure does not act