As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. AIR CONDITIONING AIR FIRST SMELLED LIKE DIRTY SOCKS, BUT THEN SEEMED MORE SMOKY AND TOXIC. FOUND HYDRAULIC LINE LEAKING. PERFORMED APU WASH ON MCM CARD 49-97-11, PACK BURN OUT ON MCM CARD 21-92-12 AND ODOR TROUBLE SHOOTING CARD 05-96-70. ACCOMPLISHED ATBT FOR ACCURACY LEAKING HYDRAULIC LINE. FOUND HYDRAULIC LINE B-NUT LOOSE AND RE-SECURED PER AMM 29-00-00. OPS AND LEAK CHECK GOOD.