As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, DURING CLIMB THE CREW REPORTED MAIN PITCH INOP WARNING ON EICAS. CREW PERFORMED AIR RETURN BACK TO IAD. IAD MX REMOVED AND REPLACED HORIZONTAL STABLIZER CONTROL UNIT IAW EMB145 AMM 27-40-01 AND PERFORMED OPERATIONAL CHECKS SUCCESSFULLY. ACFT WAS APPROVED FOR RETURN TO SERVICE.