Brake Pressure Applied/Brake Deactivator Switch

WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2004 Mercury Sable, 2004 Mercury Mountaineer, 2004 Mercury Monterey, 2004 Mercury Marauder, and 2004 Mercury Grand Marquis. However, it is still accessible from the selected car via links, so may be relevant.

The brake pressure applied (BPA) switch also sometimes called the brake deactivator switch for vehicle speed control deactivation. Is a normally closed switch, witch supplies battery positive voltage (B+) to the PCM when the brake pedal is NOT applied. When the brake pedal is depressed, the normally closed switch will open and power is removed from the PCM.

On some applications the normally closed BPA switch along with the normally open brake pedal position (BPP) switch are used for a brake rationality test within the PCM. The PCM misfire monitor profile learn function can be disable if a brake switch failure occurs. If one or both brake pedal inputs to the PCM did not change states when they were expected to a diagnostic trouble code P1572 can be set by the PCM strategy.