FixVault

Pressure "Hold" Control (Abs Active)

The inlet solenoid valve is energized, so the inlet port is closed.

On the other hand, the outlet solenoid valve is de-energized, so the output port is also closed. In this state, all the passages connecting the wheel cylinder, master cylinder and reservoir are blocked. As a result, the fluid pressure in the wheel cylinder is held unchanged.

During this phase of ABS operation, the pump motor continues operating.

NOTE: For simplicity of explanation, operation of the H/U is represented by operation of a single wheel circuit.
Fig 1: Hydraulic Control Unit Operation Diagram (Pressure Hold Control, ABS Active)
G08260364Courtesy of SUBARU OF AMERICA, INC.