Operation - Hydraulic Circuits And Valves: Notes
WARNING: This page is about a different car, the 2006 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
The hydraulic fluid control valves within the HCU control the flow of pressurized brake fluid to the wheel brakes during the different modes of ABS braking and traction control. The following paragraphs explain how this works. For purposes of explanation only, the following diagrams show only one hydraulic circuit, the Right Front wheel braking circuit.