SsangYong Rodius (2013 year). Service manual - part 166

09-17

4891-01

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.

09-18

(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.

09-19

4891-01

4) ARP (Active Roll-Over Protection)

The ARP (Active Roll-over Protection) system is a safety assistant device that minimizes, by controlling 

brakes and the engine, the physical tendency of the vehicle rollover during sharp lane changes or U-

turns. For the system, software is added to the existing ESP system and no additional device or switch 

is needed. One must note that the ARP system, just as general assistant devices including the ABS, is 

only a safety assistant device using the ESP system and its function is useless when the situation 

overcomes the physical power. Following picture shows how the ARP compensates the vehicle 

position by varying each wheel's braking power to overcome the physical tendency of the vehicle 

rollover during sharp turns.

The vehicle driving condition is controlled by the internally programmed logic according to the input 

signals from wheel speed sensor, steering angle sensor and lateral sensor.

09-20

During the ARP operation, vehicle safety (rollover prevention) takes the first priority and thus, 

stronger engine control is in effect. Consequently, the vehicle speed decreases rapidly, so the 

driver must take caution for the vehicle may drift away from the lane.

The ARP function is still available even when turning off the ESP system by ESP OFF switch. 

However, if the ESP system is shut off due to a system failure, the ARP system is also not 

available.

- 

-