As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT INTO DTW, THE CABIN ALTITUDE WARNING HORN SOUNDED. CABIN ALTITUDE WAS 10,000 FEET. AN EMERGENCY DESCENT WAS INITIATED FROM FL240 TO 10,000 FEET. FLIGHT CONTINUED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED BOTH PRESSURE RELIEF VALVES WITH SERVICEABLE UNITS.