2012 SSANGYONG RODIUS ECU

09-34891-01
1. SPECIFICATIONS
1) Pressure Sensor
UnitDescription
Location
ABS ESP
HECU
(Hydraulic &
Electronic Control
Unit) CPU:MCU60 (32bit)
Clock Frequency: 28MHz
Memory: 128~256 KB CPU:MCU60 (32bit)
Clock Frequency: 28MHz
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:
0.335~0.945mm,
Rear air gap:
0.309~0.958
Steering Wheel
Angle SensorN/AMaximum angular speed:
1500°/sec
Operating voltage: 9~16VUnder 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. 5V (4.75~5.25V)
Max. pressure 350bar

09-54891-01
1. ESP (Electronic Stability Program)
ESP system contains the ABS (Anti-Lock Brake System), ABD (Automatic Braking Differential),
ASR (Acceleration Slip Regulation), Cornering Control and HBA (Hydraulic Brake Assist System)
functions.
▶Cornering Control (Understeer and Overersteer) Function
This function controls the vehicle stability by applying the braking pressure on each wheel
according to the yaw rate, lateral sensing value and driver’s steering wheel control.
▶HBA (Hydraulic Brake Assist System) Function
HBA (Hydraulic Brake Assist) system helps in an emergency braking situation when the driver
applies the brake fast, but not with sufficient pressure, which leads to dangerously long braking
distance. ECU recognizes the attempt at full braking and transmits the signal calling for full brake
pressure from the hydraulic booster.

09-6
HECU(Hydraulic & Electronic Control Unit)
ESP ABS
2. LAYOUT
Name ESP ABS Location
1 HECU O O Under the battery
2 Pressure Sensor O X Under the master cylinder
3 Wheel Speed Sensor O O On wheels
4 Sensor Cluster O X Under the audio assembly
5 Steering Wheel Angle Sensor O X Under the steering wheel
Pressure Sensor
Installed Removed

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(3) ESP Control
The ESP (Electronic Stability Program) has been developed to help a driver avoid danger of losing
control of the vehicle stability due to understeer or oversteer during cornering. The yaw rate sensor,
lateral sensor and longitudinal sensor in the sensor cluster and the steering wheel angle sensor
under the steering column detect the vehicle conditions when the inner or outer wheels are
spinning during oversteer, understeer or cornering. The ESP ECU controls against oversteer or
understeer during cornering by controlling the vehicle stability using input values from these
sensors and applying the braking force to the corresponding wheels independently. The system
also controls the engine power right before the wheel spin synchronized to decelerate the vehicle
automatically in order to maintain the vehicle stable during cornering.

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3) HBA (Hydraulic Brake Assist System)
(1) Purpose
HBA (Hydraulic Brake Assist) system helps in an emergency braking situation when the driver
applies the brake fast, but not with sufficient pressure, which leads to dangerously long braking
distance. ECU recognizes the attempt at full braking and transmits the signal calling for full brake
pressure from the hydraulic booster. An inexperienced, elderly or physically weak driver may
suffer from the accident by not fully pressing the brake pedal when hard braking is required
under emergency. The HBA System increases the braking force under urgent situations to
enhance the inputted braking force from the driver.
Based on the fact that some drivers depress the brake pedal too soft even under when hard
braking is necessary, the HECU system is a safety supplementary system that builds high braking
force during initial braking according to pressure value of the brake pressure sensor and the
pressure changes of the pressure sensor intervals.
When the system is designed to apply high braking force when brake pedal is depressed softly by
an elderly or physically weak driver, the vehicle will make abrupt stopping under normal braking
situation due to high braking pressure at each wheels.

09-14
(2) Operation
The brake pressure value and the changed value of the pressure sensor are the conditions in
which the HBA System operates. There are 2 pressure sensors under the master cylinder. When
the ESP ECU system determines that emergency braking is present, the pump operates, the
brake fluid in the master cylinder is sent to the pump and the braking pressure is delivered to the
wheels via the inlet valves.
If the drive depress the brake pedal slowly, the pressure change is not high. In this case, only the
conventional brake system with booster is activated.

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(2) Hydraulic Circuit of HBA
The above figure shows one front and one rear wheel and the same hydraulic circuit forms as in
the ESP operation. When HECU recognizes that it is an emergency and it is required for hard
braking, depending on the pressure value of the brake pressure sensor and pressure changes
caused by the pressure sensor timing, it operates the pump immediately to apply the brake
pressure at the wheels. Then, the pressure in the pump increases until just before the
corresponding wheel gets locked. The motor still keeps rotating and the outlet valve and the
separation valve will stay closed. When the wheel starts to lock, the HBA function cancels and
switches to ABS operation.

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▶DUMP (ESP is working) Mode
The pressure decreases just before the wheel speed drops and the wheels are locked.
The inlet valve closes and the outlet valve opens as in the ABS HECU and the oil is gathered at
the low pressure chamber while no additional oil is being supplied. Then the pump operates to
allow fast oil drainage. The shuttle valve and the separation valve do not operate while
decompression.