As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED. DURING APPROACH 4R SMOKE DETECTOR MESSAGE ON ENGINE INDICATING AND CREW ALERTING SYSTEM AND SMOKE DETECTOR IN LAVATORY CAME ON. NO ACTIVE SMOKE NOTED. ACCOMPLISHED LAVATORY SMOKE DETECTION SYSTEM OPERATIONS CHECK AT 4R, PER AMM 26-13-00. NO STATUS MESSAGE OR FAULT NOTICED.