As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EWR---CO4131, CREW REPORTED, "ON TAKEOFF GOT LND GEAR AIR/GND FAIL. THEREFORE AIRRETURNED." MAINTENANCE REMOVED AND REPLACED LEFT HAND PROXIMITY SWITCH ON SHOCKABSORBER IAW EMB145 MM #32-63-01. EXTENDED AND RETRACTED LANDING GEAR OPS.CHECKED GOOD IAW EMB145 MM #32-30-00. AIRCRAFT RETURNED TO SERVICE.