As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, FUMES CAME INTO THE CABIN THROUGH THE AIR CONDITIONING VENTS AND SET AFT LAVATORY SMOKE DETECTORS. AIRCRAFT RETURNED TO STATION. FOUND RIGHT AIR CYCLE MACHINE SURGING. REMOVED AND REPLACED RIGHT ACM AND REPLACED COALESCER BAGS.