As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: IMMEDIATELY AFTER TAKEOFF, NOTICED LEFT PNEUMATIC DUCT PRESSUREWAS LOW INDICATING APPROXIMATELY 5PSI. NO ASSOCIATED PNEUMATIC ANNUNCIATIONS OCCURRED. AIRCRAFT CABIN PRESSURIZED NORMALLY; AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT DFW. REMOVE AND REPLACED NUMBER 1 ENGINE BLEED AIR REGULATOR (AALA202407300088), PER AMM36-11-03. ALSO REMOVED AND REPLACED HIGH PRESSURE VALVE (AALA202407306695), PER AMM 36-11-06. OPERTIONAL AND LEAK CHECKS GOOD.