As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOSS OF PRESSURIZATION OCCURRED AFTER TAKEOFF. CREW DECLARED AN EMERGENCY AND FLIGHT WAS RETURNED TO DTW. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND BROKEN CLAMP ON LEFT AIR CYCLE MACHINE OUTLET DUCT. REPLACED CLAMP, OPERATIONAL CHECK NORMAL.