SsangYong Korando III (2010 year). Manual — part 236

10-11

4890-00

2) EBD (Electronic Brake-force Distribution) Warning Lamp (Brake
Warning Lamp)

EBD warning lamp when the system performs the self diagnosis and when it detects the malfunction of

EBD system. However, the brake warning lamp comes on regardless of EBD when the parking brake is

applied.

EBD warning lamp ON:

When turning the ignition switch to ON position, ABS warning lamp and the brake warning lamp

comes on for 3 seconds for self diagnosis and goes off if the system is OK (initialization mode).

When applying the parking brake, the brake warning lamp comes on.

When the brake fluid is not sufficient, the brake warning lamp comes on.

When the self-diagnosis is performing, the warning lamp comes on.

When the HECU connector is disconnected, the warning lamp comes on.

When the system is defective, ABS warning lamp and the brake warning lamp come on

simultaneously.

1.

2.

3.

4.

5.

6.

When the solenoid valve is defective

When one or more wheel sensors are defective

When ABS HECU is defective

When the voltage is abnormal

When valve relay is defective

a.

b.

c.

d.

e.

When the communication between warning lamp CAN module in meter cluster, the warning lamp

comes on.

7.

10-12

5. SYSTEM OPERATION

1) Block Diagram of ABS HECU

10-13

4890-00

2) Basic Theory of ABS Function

To give you a better understanding of the tasks and functions of ABS, we will first look at the physics

principles.

(1) Stopping distance

The stopping distance depends on the vehicle weight and initial speed when braking starts. This also

applies for vehicle with ABS, where ABS always tries to set an optimum brake force on each wheel. As

great forces are exerted between the tires and the carriageway when braking, even with ABS the wheels

may scream and rubber is left on the road. With an ABS skid mark one may be able to clearly recognize

the tire profile. The skid mark of an ABS vehicle does not however leave any hint of the speed of the

vehicle in the case of an accident, as it can only be clearly drawn at the start of braking.

(2) Brake force on a wheel

The maximum possible brake force on a wheel depends on the wheel load and the adhesion coefficient

between tire and carriageway. With a low adhesion coefficient the brake force, which can be obtained is

very low. You are bound to know the result already from driving on winter roads. With a high adhesion

coefficient on a dry road, the brake force, which can be obtained, is considerably higher. The brake

force, which can be obtained, can be calculated from below formula:

Maximum brake force

▶

FBmax = wheel load FR x coefficient of frictionMh

The braking process cannot be described sufficiently

accurately with the brake forces calculated. The

values calculated only apply if the wheel is not locked.

In the case of a locking wheel, the static friction turns

into lower sliding friction, with the result that the

stopping distance is increased. This loss of friction is

termed "slip" in specialist literature.

10-14

Slip

▶

The brake slip is the difference between the vehicle speed and the wheel circumference speed. If the

wheel locks, the slip is greatest, that is 100 %. If the wheel is running freely and un-braked, the slip is the

lowest, equal to 0 %. Slip can be calculated from the vehicle speed Vveh and the wheel speed Vw. The

equation for this is:

Vveh = 100 km/h, Vw = 70 km/h

Slip ratio (S) =

For the various road conditions, the friction

coefficients were plotted. The typical course of

the curves is always the same. The only special

feature is shown by the curve for freshly fallen

snow, for this curve increases at 100 % slip. In a

vehicle without ABS, the wheel locks on braking

and therefore pushes a wedge before it. This

wedge of loose surface or freshly fallen snow

means and increased resistance and as a result

the stopping distance is shorter. This reduction in

stopping distance is not possible with a vehicle

with ABS, as the wheel does not lock. On these

surfaces the stopping distance with ABS is

longer than without ABS. The reason for this is

based in physics and not in the Anti-Lock

System.

However, as mentioned before, ABS is not about

the stopping distance, but maneuverability and

driving stability, for the vehicle with locking

wheels without ABS cannot be steered.

Typical Slip Curves

▶

Vveh - Vw

Vveh

X 100%

S = 30%