As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT THE GATE WITH BOTH ENGINES SHUT DOWN AND EXTERNAL POWER ON THE AIRCRAFT THE CARGO SMOKE WARNING ILLUMINATED WHEN THE CARGO DOOR WAS OPENED. MAINTENANCE INSPECTED THE WIRING SYSTEM WITH NO DISCREPANCIES FOUND, BOTH CARGO SMOKE DETECTORS WERE REPLACED.