As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THRU 9000 FT THE -CABIN ALT- CAUTION MESSAGE ILLUMINATED. THE CREW FOLLOWED THE QRH BUT COULD NOT RESTORE PRESSURIZATION. THE FLIGHT RETURNED TO CLT AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE NR 2 CABIN PRESSURE CONTROLLER. OPERATIONAL CHECKS WERE GOOD. THE AIRCRAFT WAS RELEASED FOR SERVICE.