Line Pressure Control Valve
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2008 Suzuki Reno, 2008 Suzuki Forenza, 2007 Suzuki Reno, 2007 Suzuki Forenza, and 2006 Suzuki Reno. However, it is still accessible from the selected car via links, so may be relevant.
The line pressure control valve sets the general pressure level in the valve body. When gearshifts are not taking place, the line pressure varies between two levels, depending on the turbine torque. Line pressure increase linearly by time. But it has a limit point. When pressure reaches that point, excess oil pressure drains back into the oil sump.