As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED AN ABNORMAL ODOR STARTING AT ROW 11 AND STRONGER IN THE AFT AERA. THE ACFT WAS REMOVED FROM SERVICE. RAN BOTH A/C PACKS IN HOT & COLD MODES USING APU. ILLUMINATED ALL CABIN LIGHTS FOR TEST. UNABLE TO DISCERN ANY OFFENSIVE ODORS. OK FOR CONTINUED SERVICE. THE ACFT WAS RETURNED TO SERVICE.