Diagnostic Aids:

WARNING: This page is about a different car, the 1995 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.

DO NOT replace EBCM or APV for this DTC. EBCM or APV fault will not cause this DTC to set.
This DTC is set when vehicle speed reaches 35 MPH or greater and there is no 12-volt signal from brake switch.
This DTC is a soft fault that turns on BRAKE light until 12 volts is received from brake switch.
DO NOT pierce connectors, wires, seals, or insulation during testing. Doing so will lead to corrosion and failure of wiring and terminals.