As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TYS - AIRCRAFT EN ROUTE FROM CLT TO IAH WHEN THE AUTO PRESSURE SYSTEM FAIL INFLIGHT. AIRCRAFT DIVERTED BACK TO CLT AND WAS MEL (169978). IAH - MAINTENANCE REMOVED AND REPLACED THE ELECTRO PNEUMATIC OUTFLOW VALVE IAW EMB 145XR MM 21-31-03. OPS CHECK GOOD AND RELEASED TO SERVICE. LOG PAGE 2520610.