As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK. PASSING FL 320 (32,000FT) CABIN ALT WARNING HORN SOUNDED AND NOTED CABIN PRESSURE PASSING 11,000FT. ALL PRESSURE SWITCHES WERE IN NORMAL POSITION WITH NO FAIL LIGHTS. CABIN MASKS DID NOT DEPLOY. PERFORMED EMERGENCY DESCENT, SWITCHED PRESS CONTROLLER TO STBY AND STOPPED CABIN ALT PRESSURIZATION CLIMB. AUTO FAIL LIGHT CAME ON SEVERAL MINUTES AFTER SWITCH WAS IN STBY. REMOVED AND REPLACED PRESSURE CONTROLLER PER MM.