As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW PERSONNEL REPORTED SMOKE / FUMES IN CABIN AS SOON AS APU AIR STARTED ON GROUND. MAINTENANCE PERSONNEL REMOVED AND REPLACED THE APU FUEL CONTROL UNIT IAW AMM 49-30-01, OPS AND LEAK CHECK GOOD IAW AMM 49-00-00. AIRCRAFT RETURNED TO SERVICE.