Hydraulic Control Unit (HCU)

HCU controls brake fluid pressure to each caliper using solenoid controlled valves to modulate pressure to any one wheel, preventing wheel lock-up. HCU is controlled by ABS control unit. Each caliper has 2 solenoid controlled valves, one controlling input of fluid to a caliper and one controlling fluid output of fluid from a caliper. These solenoids are operated only when wheel lock-up is about to or is occurring.