Brake Pedal Position (BPP) Switch
WARNING: This page is about a different car, the 2008 Ford Pickup, 2008 Ford F550 Super Duty, 2008 Ford F450 Super Duty, and 2008 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Brake status comes from the Brake Pedal Position (BPP) switch. The BPP sensor applies battery voltage to the PCM when the brake pedal is applied. The PCM uses this input to disengage the Torque Converter Clutch (TCC), speed control and auxiliary idle (if equipped).