As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DECLARED EMERGENCY - LAV SMOKE ALARM ON LANDING. SMOKE TOILET CAUTION MESSAGE ON ARRIVAL. NO SMOKE OR FIRE PRESENT. PERFORMED OPERATIONAL TEST OF LAV SMOKE DETECTION SYSTEM IAW AMM. INSPECTED BOTH ENGINES FOR OIL CONTAMINATION IN BLEEDS. NONE FOUND. INSPECTED THE APU FOR OIL CONTAMINATION, RAN BOTH ENGINES AND APU WITH BLEEDS ON. NO SMOKE NOTED. NO TOILET SMOKE MESSAGE RECEIVED. OPS CHECKED GOOD.