As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: CAPTAIN AND FIRST OFFICER EXPERIENCED FUME EVENT AROUND 4000 FEET. SWEET CHEMICAL SMELL AFTER INITIAL DIRTY SOCKS SMELL. MAINTENANCE FOUND OIL LEAKING FROM THE APU GENERATOR AND THE APU DRAIN PLUG O-RINGS AND REPLACED THE O-RINGS PER AMM 49-49-42. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ODORS BEING NOTED.