CL TYPE S V6-3.2L SOHC (2001)
Hydraulic Control Assembly - Antilock Brakes: Description and Operation
VSA
Modulator Unit
The modulator unit consists of the four inlet solenoid valves, four outlet solenoid valves, two front apply valves, two front dump valves, reservoir,
relief valves, regulator valve, cut-off valve, pressure piston, ADS pump, VSA pump, and pump motor.
The modulator controls the brake fluid pressure directly. It is a circulating-type modulator because the brake fluid circulates through the caliper, the
reservoir, and the master cylinder.
The hydraulic control has three modes: pressure intensifying, pressure retaining, and pressure reducing.
The hydraulic circuit is an independent four channel type, one channel for each wheel.
Modulator Operation
Conventional brake mode
The brake fluid is provided to the brake calipers through four inlet valves. In ABS mode, the VSA control unit drives four inlet valves, four outlet
valves, the ABS pump, and the pump motor the same as conventional ABS.
VSA mode (pressure intense tying operation) In pressure intensifying operation, the apply valve opens, the dump valve closes, and pump motor
operates. The cutting valve is closed by the brake fluid for VSA control pressing on the pressure piston. At the same time, the brake fluid in the
pressure chamber provides pressure to the brake caliper.
