VSA System Description

VSA Control Unit Inputs and Outputs for 46P Connector

 

Terminal number Wire color Terminal sign Description Measurement (Disconnect the VSA
control unit 46P connector) 
Terminal Conditions Voltage 
RED/ YEL ST-A Detects steering angle sensor signal 2-GND Ignition switch ON (II)
Turn steering wheel very slowly 
About 1-4 V alternately 
BLU/ RED WALP Drives ABS indicator 4-GND Ignition switch ON (II) Battery voltage 
WHT/ BLK STOP Detects brake switch signal 6-GND ——— ——— 
BLU/ YEL RR-GND Detects right-rear wheel sensor signal ——— ——— ——— 
PNK/ BLK VSA WL Drives VSA indicator 9-GND Ignition switch ON (II) Battery voltage 
10 GRY/ RED RL-GND Detects left-rear wheel sensor signal ——— ——— ——— 
11 YEL/ RED RL +B Detects left-rear wheel sensor signal positive ——— ——— ——— 
13 BRN/ WHT FL-GND Detects left-front wheel sensor signal ——— ——— ——— 
14 BLU OFF SW Detects VSA off switch signal 14-GND Ignition switch ON (II) Press button Battery voltage 
Released button 0 V 
15 RED/ WHT K-LINE Communications with HDS ——— ——— ——— 
16 BRN/ YEL EBD Drives brake system indicator 16-GND Ignition switch ON (II) Battery voltage 
25 YEL/ RED ST-B Detects steering angle sensor signal ——— ——— ——— 
26 BLU/ WHT ST-Z Detects steering angle sensor signal ——— ——— ——— 
27 GRN/ RED PARK Detects parking brake signal 27-GND Ignition switch ON (II) Lever pull 0 V 
Lever released Battery voltage 
28 BLU FR-GND Detects right-front wheel sensor signal ——— ——— ——— 

Terminal number Wire color Terminal sign Description Measurement (Disconnect the VSA
control unit 46P connector) 
Terminal Conditions Voltage 
29 GRN/ BLK FR +B Detects right-front wheel sensor signal positive ——— ——— ——— 
30 GRN/ YEL RR +B Detects right-rear wheel sensor signal positive ——— ——— ——— 
33 YEL/ BLK SVCC Power source for the sensors ——— ——— ——— 
34 BLU/ ORN FL +B Detects left-front wheel sensor signal positive ——— ——— ——— 
35 ORN SGND Ground for the sensors ——— ——— ——— 
37 GRN/ YEL ACT LMP Drives information indicator 37-GND Ignition switch ON (II) Battery voltage 
38 RED CAN-L F-CAN communication circuit ——— ——— ——— 
39 WHT CAN-H F-CAN communication circuit ——— ——— ——— 
40 YEL IG1 Power source for activating the system 40-GND Ignition switch ON (II) Battery voltage 
43 BLK GND2 Ground for the VSA-modulator control unit ——— ——— ——— 
44 WHT/ GRN +B FSR Power source for the fail-safe relay 44-GND At all time Battery voltage 
45 WHT/ RED MR +B Power source for the motor relay 45-GND At all time Battery voltage 
46 BLK GND1 Ground for the pump motor ——— ——— ——— 

ABS Features

When the brake pedal is pressed while driving, the wheels can lock before the vehicle comes to a stop. In such an event, the maneuverability of the vehicle is reduced if the front wheels are locked, and the stability of the vehicle is reduced if the rear wheels are locked, creating an extremely unstable condition. The ABS precisely controls the slip rate of the wheels to ensure maximum grip force from the tyres, and it thereby ensures maneuverability and stability of the vehicle.
The ABS calculates the slip rate of the wheels based on the vehicle speed and the wheel speed, then it controls the brake fluid pressure to reach the target slip rate.

Grip Force of Tyre and Road Surface 

TCS Features

The TCS provides low speed traction. When a drive wheel loses traction on a slipperly road surface and starts to spin, the VSA control unit sends a brake signal to the modulator unit, which applies brake pressure to slow the spinning wheel. At that time, the VSA control unit sends a traction control signal to reduce engine power.

 

VSA System Features


Oversteer control


 

Understeer control (in acceleration)


 

Modulator Unit


The modulator unit consists of the inlet solenoid valve, outlet solenoid valve, VSA normally open (NO) solenoid valve, VSA normally closed (NC) solenoid valve, reservoir, pump, pump motor, and the damping chamber.
The modulator controls the caliper fluid pressure directly. It is a circulating-type modulator because the brake fluid circulates through the caliper, the reservoir, and the master cylinder.
The hydraulic control has three modes: Pressure intensifying, pressure retaining, and pressure reducing.
The hydraulic circuit is an independent four channel type, one channel for each wheel.

ABS Control


Pressure intensifying mode

VSA NO valve open, VSA NC valve closed, inlet valve open, outlet valve closed.
Master cylinder fluid is pumped out to the caliper.

Pump motor

When starting the pressure reducing mode, the pump motor is ON. When stopping ABS operation, the pump motor is OFF.
The reservoir fluid is pumped out by the pump, though the damping chamber, to the master cylinder.

 

Pressure retaining mode

VSA NO valve open, VSA NC valve closed, inlet valve closed, outlet valve closed.
Caliper fluid is retained by the inlet valve and outlet valve.

 

Pressure reducing mode

VSA NO valve open, VSA NC valve closed, inlet valve closed, outlet valve open.
Caliper fluid flows through the outlet valve to the reservoir.

 



TCS Control


Pressure intensifying mode

VSA NO valve closed, VSA NC valve open, inlet valve open, outlet valve closed, pump motor ON.
The reservoir and master cylinder fluid is pumped out by the pump, through the damping chamber, to the front caliper.

 

Pressure retaining mode

VSA NO valve open, VSA NC valve open, inlet valve closed, outlet valve closed, pump motor ON.
Front caliper fluid is retained by the inlet valve and outlet valve.

 



Pressure reducing mode

VSA NO valve closed, VSA NC valve open, front inlet valve closed, front outlet valve open, pump motor ON.
Caliper fluid flows through the outlet valve to the reservoir.

 

VSA Control


Pressure intensifying mode

VSA NO valve closed, VSA NC valve open, inlet valve open, outlet valve closed, pump motor ON.
The reservoir and master cylinder fluid is pumped out by the pump, through the damping chamber, to the front and rear calipers.

 



Pressure retaining mode

VSA NO valve closed, VSA NC valve open, inlet valve closed, outlet valve closed, pump motor ON.
Front and rear caliper fluid is retained by the inlet valve and outlet valve.

 

Pressure reducing mode

VSA NO valve closed, VSA NC valve open, inlet valve closed, outlet valve open, pump motor ON.
Caliper fluid flows through the outlet valve to the reservoir.