As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INITIAL CLIMB OF FLT 7187, CREW RECEIVED A SMOKE - TOILET WARNING. AIRCRAFT PERFORMED AN AIR-RETURN TO DEPARTURE STATION, LANDING WITHOUT INCIDENT. MAINTENANCE INSPECTED A/C WITH NO EVIDENCE OF SMOKE OR FIRE. PERFORMED OPS CHECK OF LAV SMOKE DETECTOR. NO FAULTS NOTED. RAN A/C WITH PACKS ON FULL HEAT IN BOTH AUTO & MANUAL. UNABLE TO DUPLICATE FAULT. A/C RETURNED TO SERVICE.