As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FIRE WARNING WILL NOT TEST. FOUND APU FIRE HARNESS CONNECTOR D40060P TO BE LOOSE. TIGHTENED CONNECTOR, OPS CK GOOD REF AMM 26-10-00. IMMEDIATELY REPEATED, APU DET INOP LIGHT ILLUMINATED. REPLACED APU LOWER OVERHEAT DETECTOR ASSY AS RECOMMENDED. OPS CK GOOD NO FAULTS AT THIS TIME. REF MM 26-15-01.