As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT RETURNED TO FIELD WHEN AFTER TAKEOFF THE CREW RECEIVED A CABIN ALTITUDE WARNING WHILE PASSING THROUGH 17,000 FEET. MAINTENANCE INSPECTED THE AIRCRAFT AND REPLACED THE NR 2 SAFETY VALVE. OPERATIONAL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.