As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: AFTER TAKE OFF SMELLED BURNING ODOR IN FLIGHT DECK AND CABIN; AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT MIA. FOUND LEFT HAND RECIRCULATION FAN FAULTY. REMOVE AND REPLACED LEFT HAND RECIRCULATION FAN. PER AMM 21-25-02.