As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DECLARED AN EMERGENCY, RETURNED TO ATL DUE TO BURNING ODOR NEAR L1 DOOR. RAN BOTH ENGINES, COMPLETED P-TRAK FUME SURVEY, INSPECTED AREA AND REPLACED RECIRCULATION FILTERS. NO TROUBLE FOUND, NO ODORS. OPS CHECK GOOD. (8821166) AIRCRAFT WAS GROUNDED