As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 4490 EWR-CREW REPORTED MAIN PITCH TRIM INOP ON EICAS DURING CLIMB AND PERFORMED AIR RETURN BACK TO EWR WITHOUT INCIDENT. EWR MX REMOVED AND REPLACED HORIZONTAL STABILIZER CONTROL UNIT BUT DID NOT FIX. EWR MX ALSO REMOVED AND REPLACED HORIZONTAL STABILIZER ACTUATOR IAW EMB145 AMM 27-40-02 WITH OPERATIONAL CHECK SUCCESSFUL. ACFT WAS APPROVED FOR RETURN TO SERVICE.