As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD - FLT 371 - EN ROUTE IAD-DFW - DURING TAKEOFF, DETECTED A LOUD BANG AND VIBRATION AT CABIN. RETURNED IAD AND LANDED WITHOUT FURTHER INCIDENT. REPLACED NR 2 ENGINE BLEED VAVLE. ACCOMPLISHED HIGH POWER RUN. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)