VSA System Description

VSA Control Unit Inputs and Outputs for 47P Connector

Terminal number Wire color Terminal sign Description Measurement (Disconnect the VSA control unit
47P connector) 
Terminal Conditions Voltage 
1 WHT +B-FSR Power source for the fail-safe relay 1- GND At all times Battery voltage 
2 YEL/ RED RL+B Detects left-rear wheel sensor signal 2-3 Wheel Spin wheel at 1 turn/second AC: 0.053 V or above (Reference) Oscilloscope 0.15 V peak-to-peak or above 
3 RED RL-GND 
4 BLU/ WHT FL+B Detects left-front wheel sensor signal 4-20 
5 GRN/ YEL RR+B Detects rear-right wheel sensor signal 5-6 
6 BLU/ YEL RR-GND Stopped 0.25 V-1.15 V 
11 BLU DIAG-K Communications with Honda PGM Tester or HDS ——— ——— ——— 
14 WHT CAN-H F-CAN communication circuit ——— ——— ——— 
16 WHT/ RED +B-MR Power souce for the motor relay 16-GND At all times Battery votage 

Terminal number Wire color Terminal sign Description Measurement (Disconnect the VSA cotrol unit
47P connector) 
Terminal Conditions Voltage 
17 PNK FR-GND Detects right-front wheel sensor signal 17-18 Wheel Spin wheel at 1 turn/second AC: 0.053 V or above (Reference) Oscilloscope 0.15 V peak-to-peak or above 
18 GRN/ BLK FR+B 
20 BRN/ WHT FL-GND Detects left-front wheel sensor signal 4-20 
     Stopped 0.25 V-1.15 V 
28 BLU STR-A Detects steering angle sensor signal ——— ——— ——— 
29 BLU/ ORN STR-D Detects steering angle sensor signal ——— ——— ——— 
30 RED CAN-L F-CAN communication circuit ——— ——— ——— 

Terminal number Wire color Terminal sign Description Measurement (Disconnect the VSA cotrol unit
47P connector) 
Terminal Conditions Voltage 
32 BLK GND Ground for the VSA modurator-control unit ——— ——— ——— 
33 GRY/ WHT SGND Ground for the sensors ——— ——— ——— 
34 LT GRN YAW Detects YAW rate sensor signal ——— ——— ——— 
35 ORN SVCC Power source for the sensors ——— ——— ——— 
37 GRN GLAT Detects lateral acceleration sensor signal ——— ——— ——— 
38 BLK/ RED IG1 Power source for activating the system 38-GND Ignition swich ON (II) Battery voltage 
43 BUL/ YEL STR-B Detects steering angle sensor signal ——— ——— ——— 
47 BLK MR-GND 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.