As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT RECEIVED A SMOKE LAV WARNING MESSAGE INDICATION. FLIGHT ATTENDANTS CONFIRMED NO WARNING SOUND COMING FROM ANY OF THE LAVATORIES. NO VISIBLE FIRE NOR FUMES PRESENT. REMOVED AND REPLACED THE AFT LAVATORY SMOKE DETECTOR WITH A SERVICEABLE UNIT IAW AMM. OPERATIONAL CHECKS GOODS .RAN BOTH ENGINES AND NO WARNINGS OR CAUTION MESSAGES POSTED. OK FOR CONTINUED SERVICE AT THIS TIME.