As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) NO2 CABIN PRESSURE CONTROLLER PC PORT HAD A BLANKING CAP FITTED PREVENTING THE CONTROLLER FROM SENSING CORRECT CABIN PRESSURE.THE BLANKING CAP PNO CD-3 HAD BEEN FITTED TO THE PORT DURINGTROUBLESHOOTING AND HAD NOT BEEN REMOVED. PERSONNEL/MAINTENANCE ERROR.