As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE TOILET CAUTION ON TAXI INTO GATE. INVESTIGATED, NO SMOKE IN LAVATORY. INSPECTED LAVATORY, CABIN & CARGO BAY, NO EVIDENCE OF SMOKE OR FIRE. RAN APU & ENGS WITH BOTH PACKS ON, NO SMOKE OR FUMES. R & R LAVATORY SMOKE DETECTOR IAW AMM 26-16-01. OPERATIONS CHECKED GOOD. REMOVED PLACARD & REMOVED MEL.