As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE AT FL450, CREW RECEIVED CABIN ALTITUDE ALERT, FOLLOWED BY CABIN PRESSURIZATION LOSS. CHECK LIST FOLLOWED, EMER DECENT & UNSCHEDULED LANDING PERFORMED WITHOUT INCIDENT. MX EVALUATION & FOUND CABIN PRESSURIZATION CONTROLLER AT FAULT. R & R CABIN PRESSURIZATION CONTROLLER OFF PN 2119858-10 SN 66-J0142.