there is a second "redundant" switch on the brake pedal used especially by the engine management control unit and the ABS control unit. [EL5030], [EL7023].

The "basic" switch (I030) is the "normally open" type (when the pedal is pressed, the switch closes), whilst the "redundant" switch (I035) is the "normally closed" type (when the pedal is pressed, the switch contact opens): the system checks the consistency of the "pedal pressed" information in this way.