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 AND THE AIRCRAFT RETURNED TO DFW DUE TO AN EICAS AIR ENGINE 1 BLEED ABNORMAL PRESSURE. THE AIRCRAFT LANDED SAFELY AT DFW WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE #1 ENGINE PRESSURE REGULATING VALVE PER AMM 36-11-52 AND ACCOMPLISHED A SATISFACTOIRY OPERATIONAL CHECK.