As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURN BACK, APU VERIFICATION FLIGHT. APU FAULT ILLUMINATED AT TOP OF CLIMB. SHUT DOWN APU IAW ECAM AND RETURNED TO DEPARTING STATION, REPLACED APU AIR OIL COOLER AND REGULATOR AIR OIL IAW AMM 49-91-44. OPS CK OK. ACFT OK FOR CONTINUED SERVICE. OIL COOLER FOUND BLOCKED ON INLET SIDE.