As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, THE CREW WAS ALERTED BY A CAS MESSAGE CABIN OVER PRESSURE. CREW ATTEMPTED TO CONTROL CABIN PRESSURE IN MANUAL MODE, WITHOUT SUCCESS. AIRCRAFT RETURNED TO THE FIELD, LANDED WITHOUT FURTHER INCIDENT. REPLACED THE OUTFLOW VALVE IAW MM 21-31-00. GROUND CHECKED GOOD.