As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKE OFF CLIMB ABOUT 45 SEC AFTER THE GEAR WAS BROUGHT UP WE GOT THE 'MLG BAY OVHT' WARNING MESSAGE. RAN QRH 10-11. MESSAGE WENT AWAY. REMOVED AND REPLACED LEFT MLG BAY TEMP. SENSOR IAW CRJ 900 AMM 26-14-04, PERFORMED OPS TEST OF MLG OVERHEAT DETECTION AND WARNING SYSTEM AMM 26-14-00. OPS TEST PASSED, NO FURTHER DEFECTS NOTED AT THIS TIME. A/C OK FOR SERVICE.