What was found
DURING CLIMB, THE CABIN WOULD NOT PRESSURIZE. THE FLIGHT LEVELED OFF AND THE CREW RAN THE QRH. THE FLIGHT RETURNED TO ORD AND LANDED WITHOUT FURTHER ISSUES.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
DURING CLIMB, THE CABIN WOULD NOT PRESSURIZE. THE FLIGHT LEVELED OFF AND THE CREW RAN THE QRH. THE FLIGHT RETURNED TO ORD AND LANDED WITHOUT FURTHER ISSUES.