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 BLEED AIR ( COULDN'T DETERMINE WHICH ONE). C/W DH8-400-21-012A, RAN APU AND GROUND RAN ENGINES WITH BLEEDS MAX 20+ MINS, NO FURTHER ODOR NOTICED. OK FOR CONTINUED SERVICE. COULD NOT DUPLICATE, NO PARTS REPLACED.