As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKE OFF, GEAR WAS SELECTED UP, AMBER MSG CAME ON DURING RETRACTION. CREW FOLLOWED QRH. EMERGENCY WAS DECLARED AT DESTINATION, AIRCRAFT WAS ABLE TO TAXI BACK TO GATE. NO FURTHER ISSUES.1. REMOVED AND REPLACED LANDING GEAR SELECTOR VALVE IAW CRJ 900 AMM 32-32-10-000/400-801-A01. OPS CHECKS GOOD.