
ABS OPERATION
3. Turn the ignition switch ON.
4. Check for diagnostic trouble codes using the Hi-scan (pro).
5. After completion of the repair or correction of the problem, erase the stored fault codes using the clear key on the Hi-
scan (pro).
6. Disconnect the Hi-scan (pro) from the 16P data link connector.
SYSTEM FUNCTION
1. NORMAL BRAKING
Solenoid valve
State
Valve
Passage
Pump motor
IN (NO)
OFF
OPEN
Master cylinder Wheel cylinder
OFF
OUT (NC)
OFF
CLOSE
Wheel cylinder Reservoir
Under the normal braking, voltage is not supplied to solenoid valve, inlet valve is opened and outlet valve is closed.
When the brake is depressed, brake fluid is supplied to the wheel cylindervia solenoid valve to activate the brake.
When the brake is released, brake fluid is back to the master cylinder via inlet valve and check valve.
2. DUMP MODE
Solenoid valve
State
Valve
Passage
Pump motor
IN (NO)
ON
CLOSE
Master cylinder Wheel cylinder
ON
OUT (NC)
ON
OPEN
Wheel cylinder Reservoir
Under the emergency braking, if the wheels start to lock up, HECU sends a signal to the solenoid valve to decrease
the brakefluid, then voltage is supplied to each solenoid. At this time inlet valve is closed and brake fluid is blocked
from the mastercylinder. Conversely outlet valve is opened and brake fluid passes through wheel cylinder to reservoir,
resulting in pressure decrease.
3. HOLD MODE
Solenoid valve
State
Valve
Passage
Pump motor
IN (NO)
ON
CLOSE
Master cylinder Wheel cylinder
ON
OUT (NC)
OFF
CLOSE
Wheel cylinder Reservoir
When the brake fluid pressure is maximally decreased in wheel cylinder, HECU sends a signal to solenoid valve to
keep the fluidpressure, voltage is supplied to inlet valve but it is not supplied to outlet valve. At this time inlet and outlet
valves are closed and brake fluid is kept in wheel cylinder.
4. INCREASE MODE
Solenoid valve
State
Valve
Passage
Pump motor
IN (NO)
OFF
OPEN
Master cylinder Wheel cylinder
ON
OUT (NC)
OFF
CLOSE
Wheel cylinder Reservoir
Page 3 of 6
24.04.2008
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