As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GRR - FLT 4152 - LAVATORY SMOKE INDICATION CAME ON AFTER TAKEOFF AND WENT OUT 1 MINUTE LATER. CREW DECLARED AN EMERGENCY AND RETURNED TO GRR. NO EVIDENCE OF SMOKE OR BURNING. PERFORMED OPS CHECK OF SYSTEM, SYSTEM FOUND GOOD. AIRCRAFT RETURNED TO SERVICE. (M)