As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE, FORWARD CARGO DOOR ANNUNCIATED DURING CRUISE, NON-NORMAL CHECKLIST ACCOMPLISHED. AN EMERGENCY WAS DECLARED AND DIVERTED WITHOUT FURTHER INCIDENT. AIRCRAFT WAS GROUNDED. MAINTENANCE TROUBLESHOT THE FAULT IAW MAINTENANCE MESSAGE 52-12330 IAW FIM 52-34-00-810-811. FOUND THE SENSOR S52042 DEFECTIVE. REPLACED THE SENSOR, TESTED NORMAL. OK FOR SERVICE.