Possible Causes

WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.

Possible causes are:

Damaged brake switch.
Damaged PCM.
Malfunction in module(s) connected to BPP circuit.
Misadjusted brake switch.
Open or short in BPP circuit.
Open or short in brakelight circuits.