As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT DURING CLIMB CABIN PRESSURE INCREASED TO OVER 8 PSI, AND WOULD NOT DECREASE. AIRCRAFT RETURNED TO THE AIRPORT AND USED THE MANUAL DEPRESSURIZATION SWITCH TO DEPRESSURIZE THE CABIN. VISUAL INSPECTIONS WERE CONDUCTED OF THE PRESSURIZATION SYSTEM. NO VISUAL FAULTS WERE NOTED, THRU TROUBLESHOOTING AND COORDINATION WITH THE AIRCRAFT MANUFACTURER'S SUPPORT TEAM IT WAS DETERMINED THAT THE CABIN PRESSURIZATION CONTROLLER WAS FAULTY. THE CONTROLLER WAS CHANGED AND OPS CHECKED GOOD.