As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#1515, JFK-SFO. (AIRCRAFT PERFORMED AN AIR TURN BACK TO JFK) ' ODOR EVENT- COCKPIT AND ACTIVE CABIN TRIED TO ISOLATE W/FCOM GUIDANCE BOTH PACKS PRODUCING ODOR ALL PHASES OF FLIGHT; C/W INFO NOTICE 2017-T015K. IDENTIFIED APU OIL LEAKS. ENGINE RAN FOR DECONTAMINATION. NO ACTIVE ODOR NOTED. DECONTAMINATION LEVEL C WAS ACCOMPLISHED PER TSM 05-50-00-810-831-A. AIRCRAFT IS OK FOR SERVICE.'