As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, THE CARGO SMOKE LIGHT CAME ON. IT STAYED ON FOR AT LEAST ONE MINUTE THEN WENT OFF, THIS SEQUENCE HAPPENED REPEATEDLY UNTIL ENGINE SHUTDOWN UPON RETURNING TO THE GATE. MAINTENANCE CLEANED BOTH CARGO SMOKE DETECTORS AND RETURNED THE AIRCRAFT TO SERVICE.