As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 4171 RETURNED TO THE FIELD IN PITTSBURGH DUE TO NO PRESSURIZATION IN AUTO OR MANUAL MODE. MAINTENANCE INSPECTED AND REPLACED THE PRESSURE CONTROL PANEL IN ACCORDANCE WITH DORNIER MAINTENANCE MANUAL 21-00-00. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.