SsangYong Korando III (2010 year). Service manual — part 236
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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.
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5. SYSTEM OPERATION
1) Block Diagram of ABS HECU
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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.
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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%
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