Abs Control - Honda 2004 Odyssey Service Manual

Modulator Unit
The modulator unit consists of the inlet solenoid valve, outlet solenoid valve, TCS normally open (NO) solenoid valve,
TCS normally closed (NC) solenoid valve, reservoir, pump, pump motor, and the damping chamber.
The modulator controls the caliper 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.

ABS Control

Pressure intensifying mode
TCS NO valve open, TCS NC valve closed, inlet valve open, outlet valve closed.
Master cylinder fluid is pumped out to the caliper.
Pump Motor
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 cylinder.
MODULATOR UNIT
IN
OUT
RL
Pressure retaining mode
TCS NO valve open, TCS NC valve closed, inlet valve closed, outlet valve closed.
Caliper fluid is retained by the inlet valve and outlet valve.
MODULATOR UNIT
IN
OUT
RL
MASTER CYLINDER
TCS NO TCS NC
IN
DAMPING
MOTOR
CHAMBER
OUT
M
PUMP
RESERVOIR
FR
MASTER CYLINDER
TCS NO TCS NC
IN
DAMPING
MOTOR
CHAMBER
OUT
PUMP M
RESERVOIR
FR
TCS NC TCS NO
IN
DAMPING
CHAMBER
OUT
PUMP
RESERVOIR
FL
TCS NC TCS NO
IN
DAMPING
CHAMBER
OUT
PUMP
RESERVOIR
FL
IN
OUT
RR
IN
OUT
RR
(cont'd)
19-101