As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A BURNT OIL SMELL COMING FROM THE AIR CONDITIONING SYSTEM, MORE INTENSE IN FRONT PART OF CABIN AND WORSE ON THE GROUND. MAINTENANCE FOUND APU OIL OVER-SERVICED. DRAINED EXCESS OIL, CLEANED LOAD COMPRESSOR AND PERFORMED DECONTAMINATION OF ENVIRONMENTAL CONTROL SYSTEM.