As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS WHEN APU BLEED IS TURNED ON STRONG SMELL LIKE DIRTY SOCKS. MAINTENANCE FOUND THE SOURCE OF ODOR TO BE FROM THE APU.***SUPPLEMENTAL INFORMATION: MAINTENANCE REMOVED AND REPLACED THE APU IAW JOB CARD 26L31049003. OPS CHECK GOOD.