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1. OVERVIEW
Even though a driver cuts off the power, while driving, the vehicle continues to move due to the law of
inertia. Therefore, a braking device is needed to stop the vehicle. The brake system normally uses the
frictional discs that converts the kinetic energy to the thermal energy by frictional operation. The brake
system consists of the brake disc (front wheel), brake disc or drum (rear wheel), parking brake
(mechanical type), master cylinder, booster, pedal and supply lines (pipes and hoses).
Hydraulic brake ▶
Brake pedal ▶This system uses the leverage effect and Pascal's
principle. When depressing the brake pedal, the
pedal pressure is increased by booster and is
delivered to master cylinder to generate hydraulic
pressure. The hydraulic pressure generated by
the master cylinder is delivered to the brake
caliper through the brake pipes or hoses. This
hydraulic pressure pushes the brake calipers,
accordingly the caliper pads are contacted to
brake disc to generate the braking force.
Brake pedal uses the leverage effect to apply
bigger force to the brake master cylinder.
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09-8
Pad guide bolt:
25.5~30.4Nm
Brake hose bracket
mounting bolt (12 mm):
9.8 ~ 12.8Nm
Air breather screw: 8.8 ~
10.8Nm
Caliper mounting bolt
(19mm x 2EA):
83.3 ~ 102.9Nm
Brake hose bolt
(12 mm):
19.6 ~ 29.4Nm
Wheel disc
Brake caliper
Brake hub
Brake disc
Knuckle Drive shaft Brake hoseBrake pad
Shock absorber
Brake disc
Back plate
Knuckle
2. SECTIONAL DIAGRAM
Front disc brake ▶
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Rear disc brake ▶
Caliper
Brake hose
Brake disc
KnuckleWheel disc
Brake hub
Brake disc
Fastener Tightening torque Remark
Brake pad guide bolt 25.5 ~ 30.4Nm 14 mm x 2EA
Brake caliper mounting bolt 52.9 ~ 63.7Nm 17 mm x 2EA
Brake hose bolt 19.6 ~ 29.4Nm 12mm
Brake hose bracket mounting bolt 9.8 ~ 12.8Nm 12mm
Air breather screw 8.8 ~ 10.8Nm -
1) Tightening torque
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09-10
3. SYSTEM LAYOUT
Hydraulic line ▶
Brake booster
Brake reservoir and master cylinder
Front disc brake and caliper 1.
2.
3.HECU (Hydraulic & Electric Control Unit)
Rear disc brake and caliper 4.
5.
Page 936 of 1082

10-54890-00
1. SYSTEM OVERVIEW
1) What is ABS?
When braking suddenly or braking on slippery roads, the vehicle keeps moving forward but the wheels
are locking and not rotating. If these happen, the vehicle may lose stability or rotate resulting in an
accident. ABS helps to maintain directional stability and control of the vehicle. ABS is designed to
secure more safety and increase the control of steering wheel during emergency braking situation. But,
ABS does not guarantee perfect safety beyond its physical limit. ABS in this vehicle contains EBD
function. In normal driving conditions, the brake system operates without ABS function.
2) What is EBD (Electronic Brake-force Distribution)?
EBD is an automobile brake technology that automatically varies the amount of force applied to each of a
vehicle's brakes, based on road conditions, speed, loading, etc. Always coupled with anti-lock braking
systems, EBD can apply more or less braking pressure to each wheel in order to maximize stopping
power whilst maintaining vehicular control. EBD does not operate when ABS is working.ABS effect according to braking conditions ▶
Braking on split road Maneuvering while braking
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10-6
3. G-sensor (for 4WD)
Located on the floor under
parking brake bracket in center
console.4. Rear wheel speed sensor
(for 2WD)
Located on knuckle. The
appearance is different from that
for 4WD.4. Wheel speed sensor
(for 4WD)
Located on knuckle. The
appearance of front sensor is
same with rear sensor.
2. ABS warning lamp
EBD warning lamp (ABS warning lamp +
Brake warning lamp)1. ABS hydraulic device and control unit
Located under the power steering fluid reservoir and
contains the pressure sensor.
2. COMPONENT
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4WD - Front/Rear wheel speed
sensor
2WD - Front wheel speed sensor
2WD - Rear wheel speed sensor
ECU (Electronic Control Unit) 1.
ECU calculates the wheel speed, acceleration and
deceleration with the information from wheel
speed sensor, and determines the wheel slip to
control the valve and motor.
HU (Hydraulic Unit) 2.
The hydraulic circuit contains the primary circuit
and secondary circuit for ABS operation. This unit
controls the hydraulic pressure to each wheel. If
the system needs ABS operation, the valves in
the unit operate to control HOLD, RISE and
DUMP according to ECU control logic.
Motor 3.
The motor is operated when ABS is activated. The
cam-shaped output shaft of the motor enables the
brake system to receive and supply the brake fluid
during the motor operation.
Wheel speed sensor ▶
Wheel speed sensor sends the data detected by
tone wheel to HECU.
HECU ▶
Rear wheel speed sensor in 2WD vehicle is
different from that in 4WD vehicle.
Location of rear tone wheel (A) and wheel
sensor (B) in 2WD vehicle
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3. ABS CONTROL LOGIC
The principal ABS control logic is the determination of the reference speed by choosing one wheel
meeting a certain condition, while sensing the speed information from 4 wheel speed sensors when the
vehicle is being driven.
For example, when the comparison of the reference speed with front right wheel speed shows a slip, the
control signal is determined according to whether it's deceleration or acceleration. If the control
conditions are met, the brake for the front right wheel will be got under control.