As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT THE CREW NOTED THAT THE AIRCRAFT WOULD NOT PRESSURIZE. THE CREW DECLARED EMERGENCY, RETURNED TO IAH AND LANDED WITHOUT INCIDENT. IAH- MAINTENANCE REMOVED AND REPLACED THE DIGITAL CONTROLLER, PERFORMED A OPERATIONAL CHECK AND NO DEFECTS NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.