SsangYong Korando III (2010 year). Service manual — part 555

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6. HYDRAULIC CIRCUIT OF ESP

MCP: Master Cylinder Primary

MSP: Master Cylinder Secondary

ESV: Electric Shuttle Valve

NO: Normal Open

NC: Normal Close

LPA: Low Pressure Accumulator

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Circuit description

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When compared to the vehicle equipped with ABS/EBD only, the internal hydraulic circuit has a

normally-open separation valve and a shuttle valve in primary circuit and in secondary circuit.

When the vehicle brakes are not applied during engine running or when applying the non-ABS operating

brakes, the normally-open separation valve and the inlet valve are open, whereas the normally-closed

shuttle valve and the outlet valve are closed.

When the ESP system is operating, the normally-open separation valve will be closed by the solenoid

valve operation and the hydraulic circuit will be established by the shuttle valve. Then, the inlet and outlet

valves will be closed or open depending on the braking pressure RISE, HOLD or DUMP conditions.

Flashing warning lamp and warning sound during ESP operation

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When the ESP operates while the vehicle is moving, the ESP warning lamp on the instrument panel

flickers and the buzzer sounds at every 0.1 second. The ESP lamp operation is to inform a driver that the

vehicle is extremely unstable.

The ESP system is just a supplementary system for the vehicle and it cannot control the vehicle over the

physical limit. Do not solely rely on the system but be advised to drive the vehicle safely.

Drive feeling during ESP operation

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When the ESP system activates, the driving feeling can be different depending on vehicle driving

conditions. For example, it will feel different when the ESP system is activated while the ABS is operated

by depressing the brake pedal and when the ESP system is in control without the brake pedal

depressed on the same curve.

If the ESP system operates with the brake applied, the brake pressure will be increased on the

corresponding wheel which already has braking pressure for the ESP controls. In other words, the ESP

system would make the driver feel more abruptly braked compared to the situation that the braking

pressure is applied to wheel which had no braking force.

Noise and vibration that driver senses during ESP operation

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The ESP system may transfer noise and vibration to a driver due to the pressure changes caused by the

motor and valve operations in a very short period of time.

Extreme cornering will trigger the ESP operation and this will make the driver sense noise and vibration

due to sudden brake application.

Also, the ESP system controls the engine power. Therefore, the driver may notice the engine power

decreases even when the accelerator pedal is depressed.

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1) Idling and Normal Braking Condition

In this position, the separation valve and the inlet valve are open (normal open), the electrically operated

shuttle valve and the outlet valve are closed.

When the brake is applied under these conditions, the brake fluid will be sent to each wheel via the

separation valve and inlet valve.

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2) 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.