As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE TOWER REPORTED A VAPOR TRAIL COMING FROM THE NR 2 ENGINE. THE ACFT RETURNED TO DEPARTURE WITHOUT INCIDENT. MAINTENANCE INSPECTED THE ACFT AND FOUND THE LT WING OTBD FLAPPER VALVE TO BE LEAKING. MAINTENANCE R & R THE AFFECTED FLAPPER VALVE, OPERATIONALLY TESTED WITH NO DEFECTS AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.