As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS LEAVING 8000', LOST BOTH CABIN PRESSURIZATION SYSTEM. HAD TO GO TO MANUAL MODE TO CONTROL. MAINTENANCE REPLACED OUTFLOW VALVE IAW AMM 21-31-5. OPERATIONAL TEST OF THE PRESSURE CONTROL AND MONITORING NORMAL IAW AMM 21-31-00-710-002-A.