As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JUST PRIOR TO SHUTTING MAIN CABIN DOOR, A STRONG ODOR OF SOMETHING BURNING AND BOTH THE CABIN AND FLT DECK FILLED WITH SMOKE. TURNED RECIRCULATION FAN OFF AND ODOR WENT AWAY. PAX SMELLED ODOR AND SAW SMOKE. FOUND LAVATORY EXHAUST FAN FAILED. R & R THE EXHAUST FAN IAW AMM 21-23-93. OPS CHECKED GOOD. ACFT OK FOR SERVICE.