As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CHEMICAL ODOR SMELL BY FLIGHT CREW WITH REPORTED NOSE IRRITATION AND HEADACHE. REMOVED AND REPLACED APU PER TASK CARD 26L31049005. SUP WILL SUBMIT APU TEARDOWN REPORT UPON RECEIPT. HONEYWELL COULD NOT CONFIRM REASON FOR REMOVAL - NO SIGNS OF INGESTION OR LEAKS FOUND DURING APU SHOP VISIT. REPLACEMENT OF HEPA FILTERS AND / OR CLEANING OF APU MAY HAVE RESULTED IN CLEARING ODOR.