SYSTEM DESCRIPTION FUNCTION DESCRIPTION (a) ABS (Anti-lock Brake System)
(1) The ABS helps prevent the wheels from locking when the brakes are applied firmly or when braking on a slippery surface.
(b) EBD (Electronic Brake force Distribution) (1)
The EBD control utilizes ABS, and performs proper brake force
distribution between the front and rear wheels in accordance with
driving conditions. When braking while cornering, it also controls the
brake forces of the right and left wheels, helping to maintain vehicle
stability. (c) BA (Brake Assist) (1)
The primary purpose of the brake assist system is to provide auxiliary
brake force to assist the driver if the driver cannot generate a large
enough brake force during emergency braking, thus helping to maximize
the brake performance of the vehicle. (2) If the
brake booster malfunctions and the skid control ECU (brake actuator
assembly) judges that the brake pedal force applied by the driver is not
sufficient to ensure adequate braking force, brake assist is used to
enhance the braking force. (d) TRAC (Traction Control) (1)
The TRAC system helps prevent the drive wheels from slipping when the
driver depresses the accelerator pedal excessively when starting off or
accelerating on a slippery surface. (e) VSC (Vehicle Stability Control)
(1)
The VSC system helps prevent the vehicle from slipping sideways as a
result of strong front or rear wheel skid during cornering. (f) Hill-start Assist Control
(1)
When starting uphill, this control maintains the brake hydraulic
pressure to the 4 wheels, in order to momentarily help to prevent the
vehicle from descending backward. (g) Trailer Sway Control (1)
If the vehicle is towing a trailer with an inappropriate hitch load,
trailer sway could be caused by crosswinds, imbalance caused by the
load, or the driver's steering. Trailer sway control reduces trailer
sway by controlling the engine output and the braking of each wheel. (h) AUTO LSD (Auto Limited Slip Differential)
(1)
For 2WD vehicles and 4WD vehicles in 2H mode, the AUTO LSD will operate
with the VSC OFF switch (traction control switch) on (TRAC OFF or AUTO
LSD mode) and the accelerator pedal depressed. The
AUTO LSD system is used to restrain brake pressure and reduce
differential movement, thus transmitting drive torque to the other drive
wheel to ensure startability under the following conditions:
- Wheels run off the road.
- Drive wheels slip when starting on a slope with one wheel on snow/ice.
HINT: Depressing the brake pedal cancels control of the AUTO LSD system.
FUNCTION OF COMPONENTS |
Component | Function | |
Brake Actuator Assembly |
Skid Control ECU | Judges
the vehicle driving condition based on the signals from each sensor,
and sends the brake control signals to the brake actuator assembly. | |
Master Cylinder Pressure Sensor |
Assembled in the brake actuator assembly, detects the master cylinder pressure. | |
Pump Motor | Drives the pumps inside the brake actuator assembly. | |
Solenoid Valves |
- The hydraulic circuit has 2 master cylinder cut solenoid valves, 2
reservoir cut solenoid valves, 4 pressure holding solenoid valves and 4
pressure reduction solenoid valves.
- Change the fluid path based on the signals from the skid control ECU
during the operation of the brake control system functions, in order to
control the fluid pressure applied to the wheel cylinders.
| | Skid Control ECU |
ABS Motor Relay | Supplies power to the pump motor. | |
ABS Solenoid Relay | Supplies power to the solenoid valves. | |
Speed Sensor | Detects the wheel speed of each of the 4 wheels. | |
Stop Light Switch Assembly |
Detects the brake pedal depressing signal. | |
VSC OFF Switch (Traction Control Switch) |
- For 2WD vehicles or 4WD vehicles in 2H mode: Operation of the VSC OFF
switch (traction control switch) changes the vehicle from normal mode to
TRAC OFF mode to AUTO LSD mode to VSC OFF mode.
- For 4WD vehicles in 4H or 4L mode: Operation of the VSC OFF switch
(traction control switch) changes the vehicle from normal mode to VSC
OFF mode.
| | ECM |
- Sends the throttle position signal, accelerator pedal position signal, engine speed signal etc. to the skid control ECU.
- Based on the signals from the skid control ECU, controls the engine output.
| | Airbag Sensor Assembly |
Yaw Rate and Acceleration Sensor |
- The airbag sensor assembly incorporates the yaw rate sensor and acceleration sensor.
- The yaw rate sensor detects the vehicle's yaw rate.
- The acceleration sensor detects the vehicle's longitudinal and lateral acceleration.
- The airbag sensor assembly sends the detection signals from the yaw rate
sensor and acceleration sensor to the skid control ECU via CAN
communication.
| | Spiral with Sensor Cable Sub-assembly |
Steering Angle Sensor | Detects the steering direction and angle of the steering wheel. | |
Combination Meter Assembly |
ABS Warning Light | Illuminates to alert the driver when the skid control ECU detects a malfunction in the ABS. | |
Brake Warning Light |
- Illuminates to alert the driver when the skid control ECU detects a malfunction in the EBD or brake system.
- Illuminates to alert the driver when the brake fluid level is low.
| | TRAC OFF Indicator Light |
| | VSC OFF Indicator Light |
Illuminates to inform the driver when VSC OFF mode or AUTO LSD mode is entered. | |
Slip Indicator Light |
- Blinks to inform the driver when the TRAC or VSC system is performing control.
- Illuminates to alert the driver when the skid control ECU detects a malfunction in the TRAC and/or VSC system.
| | AUTO LSD indicator light |
Illuminates to inform the driver that AUTO LSD is ready to operate | |
Brake Master Cylinder Reservoir Sub-assembly |
Brake Fluid Level Warning Switch |
Detects the brake fluid level. | |
Brake Pedal Support Assembly |
Brake Pedal Load Sensing Switch |
Detects the brake pedal load. | | 
