Brake Pedal Position (BPP) Switch
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
The Electric brake booster provides the stoplamp circuit and brake pedal position switch circuit signals that are sent to the PCM.
When the brake pedal is applied, an electrical signal from the stoplamp circuit to the PCM deactivates the system. Under increased brake pedal effort, the BPP switch opens and removes the ground signal from the PCM input circuit releasing the throttle, immediately deactivating the system.