VSA System Description - Components

Components

The VSA system consists of the following primary components:

VSA modulator-control unit
Wheel speed sensors
VSA OFF switch
System indicator

For locations of each component on vehicle, refer to Component Location Index , and for indicator functions, refer to How to Troubleshoot the VSA system .

VSA Modulator

The VSA modulator unit consists of the inlet solenoid valve, outlet solenoid valve, VSA NO (normally open) solenoid valve, VSA NC (normally closed) solenoid valve, reservoir, pump, pressure sensor, and pump motor. The hydraulic control has four modes; pressure intensifying, pressure retaining, pressure reducing, and pressure intensifying mode (VSA).

Courtesy of HONDA, U.S.A., INC.

Mode	VSA NOSolenoidValve	VSA NCSolenoidValve	InletSolenoidValve	OutletSolenoidValve	Brake Fluid
Pressure intensifying mode	open	closed	open	closed	Tandem motor cylinder fluid is pumped out to the caliper.

Mode	VSA NOSolenoidValve	VSA NCSolenoidValve	InletSolenoidValve	OutletSolenoidValve	Brake Fluid
Pressure retaining mode	open	closed	closed	closed	Caliper fluid is retained by the inlet and outlet solenoid valves.
Pressure reducing mode	open	closed	closed	open	Caliper fluid flows through the outlet solenoid valve to the reservoir.
Pressure intensifying mode (VSA)	closed (current control)	open	open	closed	Tandem motor cylinder fluid is pumped out by the pump through the VSA NC solenoid valve to the caliper. Caliper fluid pressure exceeds tandem motor cylinder pressure. The VSA modulator unit controls the amount of intensified fluid pressure to respond to each mode through current control of VSA NO solenoid valve.

Wheel Speed Sensor

The VSA system uses four wheel speed sensors to monitor individual wheel speed. The wheel speed sensor is a semiconductor, Hall effect sensor, and detects the magnetic field of a magnetic encoder installed on the inner sealing surface of each hub and wheel bearing assembly. The frequency of the sensor output signal is proportional to the speed of the wheel and this signal information is sent to the VSA control unit.

Courtesy of HONDA, U.S.A., INC.