Diagnostic Aids:

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

DO NOT replace EBCM for this DTC. EBCM fault will not cause this DTC to set. If voltage readings are low or varying, battery, charging system, or intermittent connections could be the cause. Check these areas before replacing components.
This DTC is a soft fault that keeps BRAKE light on until the next ignition cycle.
DO NOT pierce connectors, wires, seals, or insulation during testing. Doing so will lead to corrosion and failure of wiring and terminals.