As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED DIRTY SOCK ODOR AT THE GATE WHILE COOLING DOWN THE AIRCRAFT WITHE THE APU. THE AIRCRAFT WAS GROUNDED. THE CREW EXITED THE AIRCRAFT AND MAINTENANCE DETERMINED THE APU WAS THE SOURCE OF THE ODOR DUE TO OIL LEAKING FROM THE TURBINE SEAL. REPLACED APU IAW TASK CARD 26L31043005 AND ACCOMPLISHED DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYSTEM PER TASK CARD 26L00021004.