As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT THE GATE WITH PASSENGERS ON BOARD, FUMES/SMOKE FILLED THE CABIN. CREW EVACUATED AIRCRAFT AND DEPLOYED RIGHT AFT SLIDE. DTW MAINTENANCE FOUND PARKING BRAKE SHUTOFF VALVE LEAKING. MAINTENANCE REPLACED VALVE AND SATURATED COALESCER BAGS. APU WAS ALSO REMOVED AND CLEANED THEN REINSTALLED. LEAK AND OPERATIONAL CHECK OK.