Honda 2004 Odyssey Service Manual page 1252

ABS Control Unit
Main Control
The ABS control unit detects the wheel speed based on the wheel sensor signal it received, then it calculates the
vehicle speed based on the detected wheel speed. The control unit detects the vehicle speed during deceleration
based on the rate of deceleration.
The ABS control unit calculates the slip rate of each wheel, and it transmits the control signal to the modulator unit
solenoid valve when the slip rate is high.
The pressure reduction control has three modes: pressure reducing, pressure retaining, and pressure intensifying.
RIGHT-REAR DETECT
WHEEL SENSOR WHEEL SPEED
LEFT-REAR DETECT
WHEEL SENSOR
WHEEL SPEED
RIGHT-FRONT DETECT
WHEEL SENSOR WHEEL SPEED
LEFT-FRONT DETECT
WHEEL SPEED
WHEEL SENSOR
Electronic Brake Distribution (EBD) Control
The electronic brake distribution (EBD) function helps control vehicle braking by adjusting the rear brake force before
the ABS operates. Based on wheel sensor signals, the ABS control unit uses the modulator to control the rear brakes
individually. When the rear wheel speed is less than the front wheel speed, the ABS control unit retains the current
rear brake fluid pressure by closing the inlet valve in the modulator. As the rear wheel speed increases and
approaches the front wheel speed, the control unit increases the rear brake fluid pressure by momentarily opening the
inlet valve. This whole process is repeated very rapidly.
DETECT
VEHICLE SPEED
REAR
DETECT
SLIP RATE
SELECT LOW
SPEED WHEEL
RIGHT-FRONT
DETECT
SLIP RATE
LEFT-FRONT
DETECT
SLIP RATE
ABS CONTROL UNIT
REFERENCE
SLIP RATE
ABS
DRIVE
CONTROL
SOLENOID
DRIVE
SOLENOID
ABS DRIVE
CONTROL SOLENOID
ABS DRIVE
CONTROL
SOLENOID
RIGHT-REAR
SOLENOID
LEFT-REAR
SOLENOID
RIGHT-FRONT
SOLENOID
LEFT-FRONT
SOLENOID
(cont'd)
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