As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD FLT 9871 THE CREW REPORTED A LAV SMOKE INDICATION DURING CLIMB. THE AIRCRAFT RETURNED TO ORD AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE PACK SYSTEM, LAV SMOKE DETECTOR AND BLEED AIR SYSYTEM. NO FAULTS WERE FOUND. THE AIRCRAFT WAS RELEASED FOR SERVICE.