As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE IN THE CABIN PRIOR TO THE FIRST FLIGHT OF THE DAY. MX TROUBLESHOT FAULT AND OPERATED ENG NR 2 WITH BOTH PACKS AND FOUND THAT THE SMOKE WAS CAUSED BY THE APU. MX RE-OPENED THE MEL FOR THE APU 3/23/05. MAINTENANCE REPLACED THE APU.