As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON CLIMBOUT AFTER THE CLIMB CHECK, HAD A GEAR DISAGREE MSTR WARNING. THE NOSE GEAR WAS THE ONE IN DISAGREEMENT. THE F/O START THE QRH, THE WARNING WENT AWAY. A/C RETURNED TO DTW AND MAINTENANCE REMOVED AND REPLACED THE NLG SELECTOR VALVE IAW AMM 32-20-00.