As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI IN, WHEN APU IS PROVIDING AIR TO AIR CONDITIONING, AN ABNORMAL ODOR IS OMITTED FROM ACFT VENTS. ACFT IS NORMAL ON ENGINE AIR. TROUBLESHOT FOUND APU INLET CONTAMINATED WITH HYDRAULIC FLUID. CLEANED INLET, PERFORMED APU DUCT BURNOUT AND REPLACED COALESCER BAGS. LEAK CHECKS GOOD. OK FOR SERVICE.