As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GRR - FLIGHT 2775 - THE CREW REPORTED A LANDING GEAR AIR/GROUND FAIL MESSAGE AFTER TAKEOFF. THE AIRCRAFT RETURNED AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND REPLACED THE RT MAIN GEAR WOW PROXIMITY SWITCH HARNESS. OPERATIONAL CHECKS WERE GOOD.