As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT AND PASSING 3000 FEET, THE LAVATORY SMOKE DETECTOR SOUNDED. THERE WAS NO SMOKE OR FUMES NOTED BY THE FLIGHT ATTENDANT. MAINTENANCE REPLACED THE LAVATORY SMOKE DETECTOR. OPERATIONAL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.