ABS SSANGYONG RODIUS 2005 Owner's Guide

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ABS SYSTEM
1. COMPONENTS AND LOCATION
Newly introduced ABS has a different shape of integrated hydraulic modulator and HECU
(Hydraulic and Electronic Control Unit) compared to existing ABS. And, the wheel speed senso
r
uses different method to detect wheel speed. The basic function of the ABS that maintains the
vehicle stability by controlling the steerability of the vehicle when braking has not been
changed.

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1) System Fuse
2) Indicators
The ABS/TCS system fuse and SB2 is
located at the fuse box in engine
compartment.
The ABS and TCS indicators are in
instrument cluster.

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ABS SYSTEM
2. INPUT AND OUTPUT DIAGRAM

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3. ABS SYSTEM DESCRIPTION
1) EBD (ELECTRONIC BRAKE FORCE DISTRIBUTION) SYSTEM
(1) System Description
As an add-on logic to the ABS base algorithm, EBD works in a range in which the intervention
thresholds for ABS control can not be reached. EBD ensures that the rear wheels are
sensitively monitored for slip with respect to the front axle. If slip is detected, the inlet valves fo
r
the rear wheels are switched to pressure hold to prevent a further increase in pressure at the
rear-wheel breaks, thus electronically reproducing a pressure-reduction function at the rear-
wheel brakes. ABS features an enhanced algorithm which includes control of the brake force
distribution between the front and rear axles. This is called Electronic Brake Distribution. In an
unloading car condition the brake efficiency is comparable to the conventional system but for a
fully loaden vehicle the efficiency of the EBD system is higher due to the better use of rear axle
braking capability.
(2) The Benefits of EBD
Elimination of conventional proportioning valve EBD utilizes the existing rear axle wheel
speed sensor to monitor rear wheel slip.
Based on many variables in algorithm a pressure hold, increase and/or decrease pulsetrain
may be triggered at the rear wheels insuring vehicle stability.
Vehicle approaches the ideal brake force distribution (front to rear).
Constant brake force distribution during vehicle lifetime.
EBD function is monitored via ABS safety logic (conventional proportioning valves are not
monitorable).
“Keep alive” function. -
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Service precautions ▶
Observe the following general precautions during any ABS/TCS service. Failure to adhere to
these precautions may result in ABS/TCS system damage.
Disconnect the EBCM harness connector before performing the electric welding procedures.
Carefully note the routing of the ABS/TCS wiring and wiring components during removal.
The ABS/ TCS components are extremely sensitive to EMI (eletromagnetic interference).
Proper mounting is critical during component service.
Disconnect the EBCM connector with the ignition OFF.
Do not hang the suspension components from the wheel speed sensor cables. The cables
may be damaged.
Do not use petroleum based fluids in the master cylinder. Do not use any containers
previously used for petroleum based fluids. Petroleum causes swelling and distortion of the
rubber components in the hydraulic brake system, resulting in water entering the system
and lowering the fluid boiling point. 1.
2.
3.
4.
5.

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(3) ELECTRICAL CIRCUIT

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ABS SYSTEM
2) HYDRAULIC CIRCUIT DIAGRAM
(1) Hydraulic Circuit of ABS
The vehicle equipped only with the ABS controls the wheel’s braking force using three 3-
channel 4-sensor method. The front wheels that are the primary circuit of the brake system is
composed of two wheel speed sensors and two channel valves system with two inlet valves
and two outlet valves. The rear wheels that are the secondary circuit of the brake system is
composed of two wheel speed sensors, one inlet valve and one outlet valve. This system is
similar to the one from the previous model.

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(2) ABS Circuit Per ABS Operation Range
Hydraulic Pressure Circuit when ABS is Not Operating ▶
No Hydraulic Pressure Circuit when ABS is Operating ▶
The hydraulic pressure in the master cylinder increases through the vacuum booster and it is
delivered to the wheel via the normal open inlet valve. At this moment, the normally-closed
outlet valve is closed. The speed of the wheel that hydraulic pressure is delivered reduces
gradually
As hydraulic pressure on each wheel increases, the wheel tends to lock. In order to prevent the
wheel from locking, the hydraulic valve modulator operates the inlet valve control solenoid to
close the inlet valve and stop the hydraulic pressure increases. At this moment, the outlet valve
is closed. This procedure helps the wheel to maintain a stable hydraulic pressure.

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ABS SYSTEM
Pressure Decreases in the Circuit when ABS is Operating ▶
Pressure Increases in the Circuit when ABS is Operating ▶
Even when the hydraulic pressure on each circuit is stable, the wheel can be locked as the
wheel speed decreases. This is when the ABS ECU detects the wheel speed and the vehicle
speed and gives the optimized braking without locking the wheels. In order to prevent from
hydraulic pressure increases, the inlet valve is closed and the outlet valve is opened. Also, the
oil is sent to the low pressure changer and the wheel speed increases again. The ABS ECU
operates the pump to circulate the oil in the low pressure chamber to the master cylinder. This
may make the driver to feel the brake pedal vibration and some noises.
As the wheel speed increases, the inlet valve opens and the wheel’s pressure increases
due to the master cylinder pressure. The oil in the low pressure chamber circulates to the wheel
by the pump and the wheel speed decreases as the hydraulic pressure at wheel increases. This
operation continues repetitively until there are no signs that the ECU is locking the wheels.
When the ABS hydraulic pressure control takes place, there may be some vibration and noises
at the brake pedal.

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(3) COMPONENTS DESCRIPTION
HECU (Hydraulic & Electronic Control Unit) ▶
Motor Pump ▶
Valve Body ▶
HECU consists of motor pump (1), solenoid
valve (2) and ECU (3).
ECU connector has 47 pins and the numbe
r
of valves in valve body is 6 when equipped
with only ABS and 12 when equipped with
ESP system.
The motor is operated when ABS is
activated. The cam-shaped output shaft o
f
the motor enables the brake system to
receive and supply the brake fluid during the
motor operation.
The cam bushing is installed between
plungers and it draws and discharges the
brake fluid.