As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TYS DURING A SCHEDULED INSPECTION, THE ALTITUDE SENSING SWITCH FOR PASSENGER OXYGEN FAILED OPS CHECK. MAINTENANCE REMOVED AND REPLACED THE ALTITUDE SENSING SWITCH IAW-EMB-145-AMM-35-20-03, OPERATIONAL CHECKED GOOD. THE REPAIR WAS SATISFACTORY AND THE AIRCRAFT WILL BE RELEASED UPON COMPLETION OF INSPECTION.