As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2058 - THE SMOKE AND MASTER WARNING LIGHT FLICKERED ON VERY BRIEFLY AND THEN TURNED BACK OFF. THE FLIGHT ATTENDANT OPENED THE BACK ACCESS DOOR AND FOUND NO SIGNS OF SMOKE. THE WARNINGS LIGHTS DID NOT COME ON AGAIN. MAINTENANCE CHECKED BOTH CARGO COMPARTMENT SMOKE DETECTORS CONNECTORS. C/W TEST PER AMM TASK 26-15-00-710-801. BOTH DETECTORS TESTED NORMAL. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.