Brake Control Warning Light Remains ON: Description
WARNING: This page is about a different car, the 2007 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
The skid control ECU is connected to the combination meter via the CAN and multiplex communications. The brake control warning light illuminates to inform the driver that there is a problem in the Electronically Controlled Brake, or a problem in the brake system that has no influence on driving.