Honda 2004 Odyssey Service Manual page 1255

ABS Components
System Description (cont'd)
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. It is a circulating-type modulator
because the brake fluid circulates through the caliper, 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.
PUMP MOTOR
Pressure intensifying mode: Inlet valve open, outlet valve closed
Pressure retaining mode:
Pressure reducing mode:
Motor operation mode:
19-54
Master cylinder fluid is pumped out to the caliper.
Inlet valve closed, outlet valve closed
Caliper fluid is retained by the inlet valve and outlet valve.
Inlet valve closed, outlet valve open
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 caliper fluid is pumped out by the pump, through the damping chamber, to the
master cylinder.
SOLENOID VALVE