As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: STRONG MUSTY ODOR COMING FROM THE PACKS ON THE GROUND AND IN THE AIR. MX VERIFIED APU SOURCE, PLACED ON MEL. MAINTENANCE REPLACED APU IAW JC 26L31049003. COMPLIED WITH ENHANCED DECONTAMINATION OF ECS IAW JC 26L00021014.