As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CARGO COMPARTMENT FIRE DETECTION LIGHT CAME ON IN FLIGHT. FOLLOWED THE CHECKLIST, FALSE ALARM. PULLED THE CARGO BAY CIRCUIT BREAKER AND CONTINUED FLT. REMOVED AND REPLACED THE CARGO BAY SMOKE DETECTOR IAW MM 26-10-21-900-801. PERFORMED OPS CHECK. OPS CHECK IS SATISFACTORY.