As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RELEASED BACK TO SERVICE AFTER EXPERIENCING A DIVERSION OR AIR TURN BACK DUE TO A MECHANICAL REASON. FOUND SOURCE OF FUMES SMELL WAS COMING FROM #2 ENG BLEED. INSP FAN BLADES AND BORO PLUGS, NO DEFECTS. ACCOMPLISHED #2 ENG WASH AND HIGH PWR RUN WITH ENG BLEED ON AND PACKS ON. NO FURTHER SMOKE OR SMELL NOTED. RECIRC FILTERS WERE REPLACED AS WELL.