As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE PILOT REPORTED THAT AFTER TAKEOFF, THE CABIN DOOR WARNING ANNUNCIATOR ILLUMINATED. DECLARED AN EMERGENCY AND LANDED BACK AT DEPARTURE WITHOUT INCIDENT. MAINTENANCE INSPECTED THE DOOR LATCHES, FOUND TO BE WITHIN LIMITS. ADJUSTED ONE OF THE SWITCHES, CONTACTED BY THE LATCHES AND OPERATION OF THE WARNING SYSTEM, FOUND NORMAL AND NO SUBSEQUENT ISSUES REPORTED.