Brake pressure sensor: Function

Fig 1: Cross-Sectional View Of Brake Pressure Sensor

Courtesy of SAAB-SCANIA OF AMERICA, INC.

When the driver depresses the brake pedal, the brake fluid is forced into the pressure duct (1). The steel membrane (2) is depressed and acts on a piezoelectric unit (3). The distribution of charge in the piezoelectric unit thus changes. This signal is amplified in the electric circuit (4) and sent to the ESP system.