NORMAL MODE
Solenoid valve | State | Valve | Motor pump | TC valve |
IN (NO) | OFF | OPEN | OFF | OFF |
OUT (NC) | OFF | CLOSE |
● In the normal driving condition, TC valve (normally open) is the passage between the master cylinder and each wheel cylinder. ● When brake pedal is applied, brake pressure is delivered to the wheel cylinders via NO-TC valve and all solenoid valves inside the hydraulic unitare deactivated. ● In case of TCS malfunction it does not affect brake operation. |
PRESSURE INCREASE MODE
Solenoid valve | State | Valve | Motor pump | TC valve |
IN (NO) | FRONT : OFF REAR : ON | FRONT : OPEN REAR : CLOSE | ON | ON |
OUT (NC) | OFF | CLOSE |
● If a front wheel spin is detected, TCS begins a brake control to decrease a wheel spin. ● Hydraulic shuttle valve (HSV) is opened. Brake fluid is supplied from the master cylinder by motor operation to the spin wheel via HSV. ● TC valve is closed (ON). Brake pressure generated from motor pump is delivered only to the front wheel. ● Inlet valve remains open to deliver the brake pressure generated from motor pump to the spinning wheels. |
PRESSURE DUMP MODE
Solenoid valve | State | Valve | Motor pump | TC valve |
IN (NO) | ON | CLOSE | ON | ON |
OUT (NC) | FRONT : ON REAR : OFF | FRONT : OPEN REAR : CLOSE |
● When the wheel deceleration is under the threshold and the wheel spin is reduced under a slip threshold, applied brake pressure is reduced to geta optimum traction force. ● Outlet valve is open to release the brake pressure and inlet valve is closed to block the pressure increase from the motor pump. ● Hydraulic shuttle valve (HSV) remains opened, TC valve is ON. ● Motor is ON, to dump the brake fluid being released from the lock-up wheel. |
PRESSURE HOLD MODE
Solenoid valve | State | Valve | Motor pump | TC valve |
IN (NO) | ON | CLOSE | ON | ON |
OUT (NC) | OFF | CLOSE |
Function improvement of the base-brake system.
Compensation for the different friction coefficients.
Elimination of the proportioning valve.
Failure recognition by the warning lamp.
FAIL CAUSE | SYSTEM | WARNING LAMP | ||
ABS | EBD | ABS | EBD | |
None | ON | ON | OFF | OFF |
1-Wheel speed sensor failure | OFF | ON | ON | OFF |
Pump malfunction | OFF | ON | ON | OFF |
Low voltage | OFF | ON | ON | OFF |
2 or more wheel speed sensor failure | OFF | OFF | ON | ON |
Solenoid valve failure | ||||
HECU malfunction | ||||
Other failure | ||||
ABS warning lamp module
The active ABS warning lamp module indicates the operating condition of the ABS.
The ABS warning lamp is turned on under the following conditions.
During the initialization phase after ignition switch ON (3 seconds).
In the event of inhibition of ABS functions by failure.
When the system ECU is shut down even though ignition power is applied.
During diagnostic mode.
EBD warning lamp module
The active EBD warning lamp module indicates the operating condition of the EBD. However, in case the parking brake switch is turned on, the EBDwarning lamp is always turned on regardless of EBD functions.
The EBD warning lamp is turned on under the following conditions.
During the initialization phase after ignition switch ON. (3 seconds).
When the system ECU is shut down even though ignition power is applied.
When the parking brake switch is ON or brake fluid is low level.
TCS lamp module
The passive TCS warning lamp module indicates the operating condition of the TCS.
The TCS warning lamp is turned on under the following conditions :
During the initialization phase after ignition switch ON (3 seconds).
In the event of inhibition of TCS functions by failure.
When the TCS OFF switch is turned on.
TCS function lamp is turned on when the TCS functions are operating (Blinking-2Hz).
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 cylinder via solenoid valve to activate the brake. When the brake is released, brake fluid is back to the master cylindervia inlet valve and check valve. |
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 brake fluid, then voltage is supplied to each solenoid. At this time inlet valve is closed and brake fluid is blocked from the master cylinder. Conversely outlet valve is opened and brake fluid passes through wheel cylinder to reservoir, resulting in pressuredecrease. |
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 fluid pressure, 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 wheelcylinder. |
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 |
If HECU determines there's no lock-up in the wheel, HECU cuts voltage to solenoid valve. So voltage is not supplied to each solenoid valve, brake fluid passes through the inlet valve to wheel cylinder, resulting in pressureincrease. |
Terminal No. | Description | Condition | Output |
9 | ● Battery power source 1 ● Solenoid valve power source | Always | System voltage |
8 | Ground | Always - In ABS control | |
7 | Diagnosis interface terminal (K-Line) | Data to the Hi-Scan | |
5 | Wheel speed sensor (Left rear) | Resistance R=1,385 ± 110Ω Min. detectable voltage 130mV peak to peak voltage at 50Hz | |
1 | Wheel speed sensor (Left front) | ||
19 | Wheel speed sensor (Right front) | ||
23 | Wheel speed sensor (Right rear) | ||
6 | Wheel speed sensor (Left rear) | ||
2 | Wheel speed sensor (Left front) | ||
20 | Wheel speed sensor (Right front) | ||
22 | Wheel speed sensor (Right rear) | ||
4 | Power input via ignition 2 switch | Ignition 2 condition | Over voltage detection : between 16.5V ± 0.5V and 20V Suspend voltage detection : between 7.0V ± 0.5 and 9.5V ± 0.5 System off : below 5.5V ± 0.5 |
25 | ● Battery power source 2 ● Motor power source | Always | ● System voltage ● Max. current : below 100A (before 100msec.) ● Rated current : below 30A (after 100msec.) |
24 | Ground | G05 | |
16 | ABS & EBD warning lamp | Energized ABS relay | Max. current : below 200mA Max. voltage 40V |
18 | Brake lamp switch input terminal | Input voltage threshold 1.00V - 2.75V 5.00V - 16.00V | |
17 | TCS warning lamp | Max. current : below 200mA | |
13 | TCS switch | Input voltage -1.0V - 16.0V | |
10 | Wheel speed sensor output (Left front) | Max current : below 10mA External resistance : 10kΩ or more | |
3 | Wheel speed sensor output (Right front) | ||
12 | Wheel speed sensor output (Left rear) | ||
14 | Wheel speed sensor output (Right front) |
