2012 SSANGYONG NEW ACTYON SPORTS Service Manual

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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.

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3) HOLD (ESP is working) Mode
The Inlet valve and outlet valve will be closed to maintain the pressure in the hydraulic circuit
applied at the wheels. By closing the valves, the hydraulic pressure at the wheels will not be lost
or supplied any more. During ESP operation, the separation valve closes and only the shuttle valve
at the pump opens.

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4) RISE (ESP is working) Mode
The shuttle valve and inlet valve will be open and the separation valve and outlet valve will be
closed. Then, the pump is operated. When ESP operates while the ABS is operating, the
pressure will be increased continuously until just before the corresponding wheel gets locked.

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5) Hydraulic Circuit of HBA
The above figure shows one front and one rear wheel and the same hydraulic circuit forms as in
the ESP operation. When HECU recognizes that it is an emergency and it is required for hard
braking, depending on the pressure value of the brake pressure sensor and pressure changes
caused by the pressure sensor timing, it operates the pump immediately to apply the brake
pressure at the wheels. Then, the pressure in the pump increases until just before the
corresponding wheel gets locked. The motor still keeps rotating and the outlet valve and the
separation valve will stay closed. When the wheel starts to lock, the HBA function cancels and
switches to ABS operation.

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7. CIRCUIT DIAGRAM
Only ABS

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Only ESP