As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT THROUGH 16,000 FT, A SMOKE AFT LAVATORY WARNING MESSAGE. WENT BACK TO THE AFT LAV AND CONFIRMED NO PRESENCE OF SMOKE OR FIRE. DUE TO A REPEAT DISCREPANCY OF THE SAME LAVATORY, REMOVED & REPLACED THE AFT LAVATORY SMOKE DETECTOR IAW AMM 26-16-01. CHECKED NORMAL.