As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE ACFT EXPERIENCED AN OVER VOLTAGE LIGHT SHORTLY AFTER ENGINE START DURING A MAINTENANCE GROUND RUN. THE OVER VOLTAGE SENSOR WAS FOUND TO HAVE FAILED. THE UNIT WAS REPLACED AND THE SYSTEM WAS GROUND FUNCTION CHECKED SERVICEABLE.