As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DIRTY SOCK ODOR COMING FROM AIRSOURCE WEMACS IN FLIGHT, IN FLIGHT DECK AFTER APU WAS TURNED ON. INSTALLED NEW SOCK - LOWERED LEFT AND RIGHT ENGINE OIL LEVELS. GROUND RUN APU & ENGINES NO ODOR NOTED WITH APU/ ENGINE BLEED AIR ON GROUND. REF MM 21-10-45