Subaru LEGACY 2002 Quick Reference Index page 418

VEHICLE DYNAMICS CONTROL (VDC) SYSTEM
VDC
7. PRESSURE "DECREASE" CONTROL WITH BRAKE PEDAL NOT DEPRESSED
The cut solenoid valve, suction solenoid valve, inlet solenoid valve and outlet solenoid valve are
all energized. This means that the ports of the cut solenoid valve and inlet solenoid valve are
closed, while those of the suction and outlet solenoid valves are open.
In this state, the pump is activated drawing the brake fluid from the reservoir and forcing it toward
the master cylinder through the open port of the suction solenoid valve. The fluid passage is
blocked by the inlet solenoid valve, so the fluid cannot flow toward the wheel cylinder. Since the
port of the outlet solenoid valve is open, on the other hand, the brake fluid in the wheel cylinder is
allowed to be drawn into the reservoir, so the fluid pressure in the wheel cylinder decreases. The
brake fluid drawn into the reservoir is raised from it and forced into the master cylinder reservoir
tank through the suction solenoid valve.
The pressure of the fluid in the passage toward the cut solenoid valve becomes higher and higher
as the pump operates since the valve is closed. When the pressure reaches a certain level, the
build-in relief valve of the cut solenoid valve opens, releasing the brake fluid into the master cylin-
der reservoir tank.
NOTE:
For simplicity of explanation, operation of the hydraulic control unit is represented by operation of
a single wheel circuit.
VDC-20