Here is the VSC description from the 2012 repair manual.
The system works by using front and rear speed sensors, steering angle sensor, yaw rate sensor, and deceleration sensor.
1. SYSTEM DESCRIPTION
The skid control ECU is built into the brake actuator.
(a) ABS (Anti-lock Brake System)
The ABS helps prevent the wheels from locking when the brakes are applied firmly or on a slippery
(b) EBD (Electronic Brake Force Distribution)
The EBD control utilizes the ABS, performing proper brake force distribution between the front and
rear wheels in accordance with the driving conditions. When the brakes are applied while
cornering, it also controls the braking forces of the right and left wheels, helping to maintain
(c) BA (Brake Assist)
The primary purpose of the brake assist system is to provide auxiliary brake force to assist drivers
who cannot generate a brake force large enough during emergency braking, thus helping to
maximize the vehicle's braking performance.
(d) TRAC (Traction Control) (for 2WD vehicles or 4WD vehicles in H2 or H4* mode)
The TRAC system helps prevent the drive wheels from slipping if the driver presses down on the
accelerator pedal excessively when starting off or accelerating on a slippery surface.
*: In H4 mode, the system performs only brake control.
(e) VSC (Vehicle Stability Control) (for 2WD vehicles or 4WD vehicles in H2 or H4 mode)
The VSC system helps prevent the vehicle from slipping sideways when front or rear wheel skidding
occurs while cornering.
(f) AUTO LSD (Auto Limited Slip Differential)
For 2WD vehicles and 4WD vehicles in H2 mode, the AUTO LSD will operate with the VSC OFF
switch on (TRAC OFF mode (AUTO LSD control)) and the accelerator pedal depressed.
The AUTO LSD system is used to apply brake pressure and limit differential slippage, thus
transmitting drive torque to the other drive wheel to ensure traction when starting under the
One of the drive wheels spins, for example, when one drive wheel is driven off of the pavement.
One of the drive wheels slips on snow/ice when starting on a slope.
The AUTO LSD is temporarily disabled when the brake pedal is depressed.
2. ABS with EBD, BA, TRAC and VSC OPERATION
(a) The skid control ECU (brake actuator assembly) calculates vehicle stability tendency based on the
signals from the 4 wheel speed sensors, the yaw rate and deceleration sensor, and the steering
angle sensor. In addition, it evaluates the results of the calculations to determine whether any
control actions (control of the engine output torque by electronic throttle control and of the brake
fluid pressure by the brake actuator) should be implemented.
(b) The slip indicator blinks and the VSC warning buzzer sounds to inform the driver that the VSC
system is operating. The slip indicator also blinks when traction control is operating, and the
operation being performed is displayed.
3. INITIAL CHECK
(a) When the vehicle speed first reaches approximately 6 km/h (4 mph) or more after the ignition
switch has been turned ON, each solenoid valve and the brake actuator motor are sequentially
activated to perform electrical checks. During the initial check, the operating sound of the motor
can be heard from the engine compartment, but this does not indicate a malfunction.
4. FUNCTION OF COMPONENTS
Front speed sensor
sensor, magnetic sensor
Detects the wheel speed and sends a signal to the skid control ECU.
The magnetic sensor rotor is equipped with north and south poles (48
poles each), which are evenly spaced around its circumference.
The magnetic field changes as the magnetic sensor rotor rotates. The
semiconductor speed sensor detects the change and outputs it as the
vehicle speed pulse.
Rear speed sensor
sensor, magnetic sensor
The skid control sensor (semiconductor speed sensor) and the sensor
rotor (magnetic sensor rotor) are installed on the rear axle carrier.
The rear speed sensor has the same structure and functions as the front
Skid control ECU
(Housed in brake
Processes the signals from each sensor to control the ABS, BA, TRAC,
VSC and AUTO LSD.
Sends and receives control signals to and from the ECM, yaw rate and
deceleration sensor, steering angle sensor, etc. via CAN communication.
Consists of the master cylinder cut solenoid valve, holding solenoid valve,
pressure reduction solenoid valve, pump motor, and reservoir, and
adjusts the brake fluid pressure applied to each wheel cylinder.
Houses the skid control ECU.
Supplies power to the pump motor.
Housed in the skid control ECU.
Supplies power to each solenoid.
Housed in the skid control ECU.
Steering angle sensor
Detects the steering extent and direction and sends signals to the skid
control ECU via CAN communication.
Has a magnetic resistance element which detects the rotation of the
magnet housed in the detection gear in order to detect the changes in
magnetic resistance and the steering amount and direction.
Yaw rate and
The yaw rate sensor detects the vehicle's angular velocity (yaw rate) in
the vertical direction based on the extent and direction of the quartz
tuning fork due to the Coriolis force.
The deceleration sensor measures the capacity of the condenser that
changes with the distance between the electrodes depending on G force,
which occurs when the vehicle is accelerated, and converts the measured
value into electrical signals.
Sends signals to the skid control ECU via CAN communication.
Master cylinder brake
fluid pressure sensor
Detects the brake fluid pressure in the master cylinder.
Housed in the brake actuator.
Controls the engine output when TRAC and VSC are operating with the
skid control ECU via CAN communication.
VSC OFF switch
For 2WD vehicles or 4WD vehicles in H2 mode: Operation of the VSC
OFF switch changes the vehicle from normal mode to TRAC OFF mode
(AUTO LSD control) to VSC OFF mode.
For 4WD vehicles in H4 mode: Operation of the VSC OFF switch
changes the vehicle from normal mode to VSC OFF mode.
ABS warning light
Illuminates to inform the driver that a malfunction in the ABS has
Blinks to indicate DTCs that relate to the ABS. (slip indicator light
illuminates at same time.)
BRAKE warning light
Illuminates to inform the driver that the parking brake is ON when the
system is normal, and when the amount of brake fluid has decreased.
Illuminates to inform the driver that a malfunction in the EBD has
TRAC OFF indicator light Illuminates when vehicle is in TRAC OFF mode.
VSC OFF indicator light Illuminates when vehicle is in VSC OFF mode.
Slip indicator light
Illuminates to inform the driver that a malfunction in the VSC and/or
TRAC system has occurred.
Blinks to inform the driver that TRAC and/or VSC are operating.
AUTO LSD indicator light Illuminates to inform the driver that AUTO LSD is ready to operate.
VSC Warning Buzzer
Housed in the combination meter assembly
Sounds intermittently to inform the driver if the temperature of brake
actuator assembly has increased excessively due to continuous operation
of TRAC, A-TRAC and AUTO LSD.
Here is an excerpt from the meter/guage system description.
Indicates vehicle speed based on signals received from brake actuator
This never copied very clearly.
I can post a link to the PDF file if anyone is interested.