Diaphragm Travel Sensor

To enable continuous monitoring of the function of the electrical activation of the active brake servo, it has a diaphragm travel sensor. This is a tracer pin that follows the movement of the diaphragm. Specifically, this sensor signal enables air pockets in the brake fluid to be found and leaks in the hydraulic system to be discovered. In the case of these problems, the travel distance of the diaphragm is less than expected for the corresponding supply of current to the diaphragm valve. The SBA control unit evaluates the signal of the diaphragm travel sensor and carries out the monitoring. If a fault is detected, the SBA control unit exits by-wire mode and changes to conventional mode. At the same time, it triggers the output of a Check Control message.