As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED RECEIVING AN AFT CARGO DOOR MESSAGE DURING INITIAL CLIMB. THE CREW RETURNED TO FIELD AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE TROUBLESHOT, R & R THE AFT CARGO DOOR WIRE HARNESS AND PERFORMED CHECKS IAW THE AMM. THE ACFT WAS RELEASED FOR SERVICE.