As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT CARGO SMOKE WARNING IN FLIGHT. WARNING CANCELED ON ITS OWN, RETURNED TO FIELD. *S/D* RESET CIRCUIT BREAKERS AND PERFORMED BITE TEST OF SYSTEM, OPERATIONALLY CHECKS NORMAL. REPLACED SMOKE DETECTION CONTROL UNIT AS A PREVENTATIVE MEASURE.