As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 4415 EWR. CREW REPORTED AFTER TAKEOFF EICAS MESSAGE LG AIR/GND FAIL AND LANDING GEAR WOULD NOT RETRACT. CREW PERFORMED AIR RETURN WITHOUT INCIDENT. EWR MX FOUND CONNECTOR P2835 WITH PINS A, B, AND C SHORTED. EWR MX REMOVED AND REPLACED RIGHT MAIN LANDING GEAR WOW HARNESS IAW EMB145 AMM32-00-03. MX PERFORMED GEAR SWING SEVERAL TIMES WITH NO FAILURES AND OPERATIONAL CHECKS SUCCESSFUL. ACFT WAS APPROVED FOR RETURN TO SERVICE.