As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A5 LAVATORY SMOKE ALARM WENT OFF INFLIGHT. NO SMOKE WAS FOUND IN LAVATORY AT TIME OF ALARM. SMOKE DETECTOR IN LAVATORY A5 CHECKED & APPROVED FOR DEFERRAL IAW MEL 26-10B AUTH 2-488DC-C. REPLACED A5 LAVATORY SMOKE DETECTOR AT ORD ON 02/15/2014. OPERATIONS CHECKED NORMAL.