2006 prius with 112,000 miles. The brake light, abs light, vsc light, and exclamation light is lit. Brakes work fine. Would this be the brake power supply going bad?
No. When the Prius is READY, check the inverter coolant reservoir for fluid turbulence. If you do not see this, then the inverter coolant pump has failed and must be replaced. (Do a search for LSC - limited service campaign, which is a recall of the pump covering your vehicle.) When the inverter overheats, the DC/DC converter shuts down which causes the skid control ECU to log DTC and turn on the warning lights that you cited.