As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FA SMELLED FUMES IN THE CABIN OF FLIGHT 3554. A/C DIVERTED TO SDF. MAINTENANCE INSPECTED A/C BAY, HYDRAULIC BAY, AND E&E BAY, NO FUMES OR SMOKE NOTED. RAN APU NR 1 & 2 PACKS INDEPENDENTLY, FOUND NO LEAKS OR FUMES PRESENT. RAN ALL FOUR ENGINES WITH ENGINE AIR PACKS SELECTED ON. COULD NOT DUPLICATE DISCREPANCY.