Anti-Lock Brake System (Abs); Operation - Honda Civic Service Manual

Anti-lock Brake System {ABS)
Operation (cont'dl
ABS Modulator
The ABS modulator consists of the inlet solenoid valve, outlet solenoid valve, reservoir, pump, pump motor and
the
damping chamber.
The modulator reduces the caliper fluid pressure directly, and it is also referred to as a circulating type because the brake
fluid
circulates through the caliper, reservoir and the master cylinder.
The hydraulic control has three modes: pressure reducing, pressure retaining, and pressure intensifying.
The hydraulic circuit is the independent four channel type, one channel for each wheel.
R F
L R
Pressure intensifying mode: Inlet valve open, outlet valve closed
Pressure retaining mode:
Pressure reducing mode:
Motor operation mode:
r N : I N L E T V A L V E { N O R M A L t Y O p E N I
OUT: OUTIET VALVE {NORMALIY CTOSED)
Master cylinder fluid is pumped out to the caliDer.
Inlet valve closed, outlet valve closed
Caliper fluid is retained by the inlet valve and outlet valve.
Inlet valve closed, outlet valve oDen
Caliper fluid flows through the outlet valve to the reservoir.
When starting the pressure reducing mode, the pump motor is ON.
When stopping ABS operation, the pump motor is OFF.
The reservoir fluid is pumped out by the pump, through the damping chamber, to the master
cvlinder.
PUMP MOTOR
19-48