As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING GEAR EXTENSION RECEIVED LANDING GEAR DISAGREE, LANDING GEAR AIR/GROUND FAIL MESSAGE WITH THREE GREEN LIGHTS. PERFORMED MANUAL GEAR EXTENSION, DECLARED EMERGENCY. PERFORMED CENTRAL MAINTENANCE SYSTEM DOWNLOAD IAW EMB AMM 45-900-00 AND FLIGHT DATA RECORDER DOWNLOAD IAW AMERICAN EAGLE WORKCARD 31-700-05. PERFORMED OPERATIONAL CHECK OF AIR/GROUND SYSTEM IAW AMERICAN EAGLE WORKCARD32-700-16 WITH NO DEFECTS NOTED. REMOVED AND REPLACED LANDING GEAR ELECTRONIC CONTROL UNIT AND PERFORMED OPERATIONAL CHECKS IAW EMB AMM. RETURNED AIRCRAFT TO SERVICE.