As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - FLIGHT 2501 - CREW RECEIVED A FIRE SYSTEM FAULT MESSAGE. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND A FWD SMOKE DETECTOR 3 FAILED CMD ON THE MAINTENANCE DIAGNOSTICS COMPUTER. A FIRE DETECTION SYSTEM TEST WAS PERFORMED AND CHECKED GOOD. NO MORE FAULTS LISTED. AIRCRAFT RETURNED TO SERVICE.