Honda Civic. Manual — part 1079

rate.

Grip force of tire and road surface

Fig. 6: Identifying Grip Force Of Tire And Road Surface Graph

Main Control

The control unit detects the wheel speed based on the wheel speed sensor signals it
received, then it calculates the vehicle speed based on the detected wheel speed.
The control unit detects the vehicle speed during deceleration based on the rate of
deceleration.

The control unit calculates the slip rate of each wheel, and transmits the control
signal to the modulator unit solenoid valve when the slip rate is high.

The hydraulic control has three modes: Pressure intensifying, pressure reducing,
and pressure retaining.

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)

Fig. 7: Identifying Hydraulic Control Unit Graph

EBD Features

The electronic brake distribution (EBD) feature helps control vehicle braking by
adjusting the rear brake force in accordance with the rear wheel load before the
ABS operates. Based on the wheel speed sensor signals, the control unit uses the
modulator to control the rear brakes individually. When the rear wheel speed is less
than the front wheel speed, the VSA modulator-control unit retains the current rear
brake fluid pressure by closing the inlet valve in the modulator. As the rear wheel
speed increases and approaches the front wheel speed, the VSA modulator-control
unit increases the rear brake fluid pressure by momentarily opening the inlet valve.
This whole process is repeated very rapidly. While this is happening, there is
kickback at the brake pedal.

Fig. 8: Identifying Electronic Brake Distribution Graph

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)

TCS Features

When a drive wheel loses traction on a slippery road surface and starts to spin, the
VSA modulator-control unit applies brake pressure to the spinning wheel and sends
engine torque control request to the ECM to slow the spinning wheel and keep
traction.

Fig. 9: Identifying Total Traction

VSA System Features

Oversteer control

Applies the brake to the front and rear outside wheels

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)

Fig. 10: Identifying VSA System - Oversteer Control

Understeer control

Applies the brake to the front and rear inside wheels

Controls the engine torque when accelerating

Fig. 11: Identifying VSA System - Understeer Control

Brake Assist Features

Brake assist helps ensure that any driver can achieve the full braking potential of
the vehicle by increasing brake system pressure in a panic situation, bringing the
vehicle into a full ABS stop.

Each time the ignition switch is turned ON (II), the VSA modulator-control unit

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)