As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: EMERGENCY POWER SUPPLY UNIT INTERNAL LOAD EMERGENCY LEFT MESSAGE DISPLAYED DURING SYSTEM TEST. MAINTENANCE RE-SECURED CANNON PLUG PER AMM 33-51-38 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK WITH NO FAULTS NOTED.