Page 605 of 796
05-6
2. 4WD SYSTEM COMPONENTS
Front axle Exterior components ▶
4WD solenoid valve
Hub & locking hub
Actuator
T/C assemblyT/C control motor
assembly
Front propeller
shaft
Rear axle
Rear propeller
shaft
Page 608 of 796
05-93240-01
4. IWE LOCKING HUB SYSTEM
1) Overview
The vacuum locking hub uses the IWE (Integrated Wheel End) system, and in this system, the
vacuum is generated only within the hub actuator.
It is structured to transmit power to the front section after the actuator hub is engaged following
the release of vacuum from the drive shaft end gear and the hub end gear.
Booster
Vacuum pump
Vacuum generation process in front hub actuator ▶
Page 609 of 796
05-10
(2) Vacuum System Related to 4WD
In 4WD mode, the TCCU blocks the
transferring of vacuum pressure from
vacuum pump to locking hub by supplying
the power to solenoid valve.Check valve
This valve allows the vacuum pressure to
flow through it in only one direction. This
prevent the vacuum from abruptly
releasing due to faulty vacuum pump.
4WD:
The vacuum pressure is released from the hub
actuator. At this time, the front hub end gear is
engaged.2WD:
The vacuum pressure pulls in the locking hub
actuator so that it will not be engaged with the
front end hub gear.
Vacuum solenoid valve
To atmosphere Block the vacuum
pressure
Hub actuator (RH)
Gear disengagedGear engaged
Page 610 of 796
05-113240-01
5. POWER FLOW
Switching 2H, 4H → 4L
TCCU
Vacuum solenoid
Locking hub operation
(Released internal vacuum)
Front propeller shaft
Front axle
Front wheelRear propeller shaft
Rear axle
Rear wheel
Transfer case
Page 645 of 796
08-18
2) Rear Brake
▶ Brake Disc
Brake disc
Lock nutCaliper
Brake hose
Backing plate
Adjusting bolt
Brake shoe Lock nut
Parking brake
operating lever
Page 649 of 796
09-34891-01
1. SPECIFICATIONS
1) Pressure Sensor
UnitDescription
Location
ABS ESP
HECU
(Hydraulic &
Electronic Control
Unit) CPU:MCU60 (32bit)
Clock Frequency:
28 MHz
Memory: 128~256 KB CPU:MCU60 (32bit)
Clock Frequency:
28 MHz
Memory:256~512 KB Under the front washer
reservoir
Wheel Speed
SensorActive type wheel speed
sensorActive type wheel speed
sensorOn each wheel
Front air gap:
0.3 ~ 1.3mm,
Rear air gap:
0.3 ~ 1.3 mm
Steering Wheel
Angle SensorN/AMaximum angular speed:
1500°/sec
Operating voltage:
9~16 VUnder the steering
wheel
Sensor ClusterN/AIntegrated with yaw rate
sensor and lateral sensorUnder the audio
assembly
Pressure Sensor
N/A Analog outputUnder the master
cylinder
Description Specification
Supplying voltage approx. 5 V (4.75~5.25 V)
Max. pressure 350 bar
Page 651 of 796

09-54891-01
2. FUNCTION
1) Term Definition
ABS: Anti-Lock Brake System ▶
When the brake pedal is abruptly depressed, the HECU calculates the slip ratio of each wheel based
on information received from the wheel speed sensors and controls the hydraulic module data quickly
and precisely in order to maintain the friction between the road surface and tire optimal (static friction).
Therefore, by keeping the friction between the road surface and tire optimal, it is possible to obtain
following effects: Enhanced steering stability, improved direction stability, reduced stopping distance
and etc.
EBD: Electronic brake-Force Distribution ▶
This is to detect the tire speed from the wheel speed sensor in order to supply the braking pressure to
the rear tires individually. In other words, the HECU measures the tire deceleration speed continuously
and controls the rear inlet valve on the hydraulic modulator to obtain optimal braking force as much as
possible. Thereby, stopping distance, braking effect and straight stability are improved.
ESP: Electronic Stability Program ▶
This is used to make the vehicle stabilized to recognize the emergency driving conditions, and to
control the brake for each wheels and the engine power when the brake system or acceleration will not
work any more in dangerous circumstances.
TCS: Traction Control System ▶
When the wheel is slipping due to an excessive engine torque while starting off or driving, this controls
the driving force (braking force + engine torque) in order to prevent the wheel from slipping through the
engine or brake control.
AYC: Active Yaw Control ▶
This has been developed to help a driver avoid danger of losing control of the vehicle stability due to
understeer or oversteer during cornering, which is a part of the ESP function.
HBA: Hydraulic Brake Assistant ▶
Developed based on the fact that elderly drivers depress the brake pedal too soft even when hard
braking is necessary, this an assist system to operate the HECU drive motor immediately and apply
high braking force to the wheels when the brake pedal is depressed softly and the vehicle should be
braked in emergency.
ARP: Active Rollover Protection ▶
This is a supplementary device for safety in ESP system and can help minimize the rollover accidents
by detecting a potential rollover situation through the brake and engine control when making sudden
lane change or turning sharply by adding only the software, without any separate device or switch.
Page 658 of 796
09-12
3. OPERATING PROCESS
1) Block Diagram of Input and Output