As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BURNING ODOR THROUGHOUT CABIN AND COCKPIT AFTER BLEED SELECTOR WENT TO NORM AT 1000' LAV SMOKE DETECTOR SOUNDED. BOTH BLEED 1 AND 2 WERE ON AND PACKS WERE IN AUTO. ODOR SUBSIDED BEFORE WE COULD ISOLATE IT'S SOURCE VIA E/A CHECKLIST. RETURNED TO FIELD. LANDING UNEVENTFUL. REPLACED NR 2 ENG IAW 6710004, GROUND RAN GOOD, NO ODOR OR DETECTOR SOUND. RETURNED TO SERVICE.