As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 3157, DURING PREFLIGHT INSPECTION, FLIGHT ATTENDANT REPORTED A STRONG ODOR IN AFT CABIN RESEMBLING FUEL OR ACETONE. AIRCRAFT REMOVED FROM SERVICE. AFTER INSPECTION OF SOURCE OF ODOR IT CAME FROM LAVATORY. RESERVICED LAVATORY SYSTEM. NO ODOR IS NOTICED AT THIS TIME. AIRCRAFT RETURNED TO SERVICE.