A sensor module for use with a master cylinder of a brake system is described, wherein the master cylinder has an input-side activation element and an underpressure region for communicating with an underpressure brake booster. The sensor module comprises an underpressure sensor for detecting an underpressure in the underpressure region of the master cylinder as well as at least one further sensor for detecting a signal transmitter which is rigidly coupled to the activation element. The underpressure sensor and the at least one further sensor are accommodated in a housing of the sensor module. An opening in the housing permits communication between the underpressure sensor and the underpressure region of the master cylinder.