VSA System Description - Hydraulic Boost Failure Compensation

Overview

If the electric brake booster system malfunctions, the operating force of the brake pedal becomes larger than under normal conditions. In this case, the hydraulic boost failure compensation uses the pressurization control of the VSA system to reduce the operating force of the brake pedal.

Control

The VSA modulator-control unit calculates control quantity based on the signals of the brake pedal position switch, the wheel speed sensors, and the pressure sensor, then increases the caliper pressure by driving the pump motor and solenoid valves.