As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT CABIN PRESSURIZATION REACHED 10,000 FEET AT 10,500 FEET. THE CREW RECEIVED AN AURAL WARNING OF CABIN PRESSURE AND THE CABIN PRESSURE INDICATION WAS SHOWING IN THE RED. THE CREW RETURNED TO KORD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE DIGITAL PRESSURIZATION CONTROLLER. OPERATIONAL CHECKS AND LEAK CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.