As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ABOUT 42 MINUTES OF FLIGHT TIME, LEVEL 1 EMERGENCY POWER ON DISPLAYED. TRIED TO RECYCLE EMERGENCY POWER SWITCH NO CHANGE. DUMPED 40,000 LBS FUEL FOR RETURN TO DEPARTURE. EPCU FAULT "ADG BATT CTL RLY/INTFC" INDICATED ON CFDS. CURRENT FAULTS, R & R EPCU IAW AMM 24-08-01 IAW FIM PROCEDURE 24-24-06-00. ALSO REPLACED LT EMERGENCY AC BUSS SENSE RELAY AS PRECAUTION. NO CURRENT FAULTS IND. OK TO CONT.