As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INFLIGHT DFW TO MEX. CREW REPORTED CABIN ALTITUDE CLIMBED TO 10,000 FEET. PASSENGER OXYGEN MASKS DID NOT DEPLOY. INITIATED RAPID DESCENT PROCEDURES. LANDED AUS WITHOUT INCIDENT. BITE CHECK OF NUMBER 2 AUTO PRESSURE CONTROLLER INDICATED FAILURE OF THE OUTFLOW VALVE ACTUATOR. REPLACED OUTFLOW VALVE ACTUATOR. SYSTEM GROUND CHECKED NORMAL OPERATION.