As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE CLIMBING OUT OF MKE, THE CREW REPORTED THAT AT AROUND 14,000FT THE CABIN ALTITUDE WAS NEARING 10,000FT WITH AUTO PRESSURIZATION. THE AIRCRAFT DESCENDED TO 10,000FT FOLLOWED THE QRH AND RETURNED TO MKE WHERE THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE AUTO PRESSURIZATION CONTROLLER AND THE PRESSURIZATION CHECKED NORMALLY AT THAT TIME.