As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DECLARED EMERGENCY DUE TO SMOKE IN CABIN AFTER SWITCHING TO APU BLEED WHEN LANDING. LT ACM PREVIOUSLY MEL FOR SIMILAR SMOKE IN CABIN SITUATION. MX PERFORMED COMPREHENSIVE TEST OF RT ACM RUNNING IT OFF ENGINE BLEED AND COULD NOT DUPLICATE PROBLEM, MEL APU. MX CLEANED APU GEARBOX VENT LINE. OPS CHECKED GOOD.