As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER TAKEOFF, WHEN THE LANDING GEAR LEVER WAS MOVED TO THE UP POSITION, LANDING GEAR DID NOT RETRACT AND RECEIVED A LANDING GEAR LEVER DISAGREE MESSAGE. THE CREW UTILIZED THE QUICK REFERENCE HANDBOOK AND WERE DIRECTED TO RETURN TO FIELD. THE CREW ALSO PERFORMED THE ABNORMAL GEAR EXTENSION CHECKLIST TO ENSURE THE LANDING GEAR WAS DOWN AND LOCK (AS IT SHOWED ON THE EICAS). THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LANDING GEAR ELECTRONIC UNIT. OPERATIONAL CHECKS AND GEAR EXTENSION/RETRACTION TESTS WERE GOOD WITH NO FURTHER DEFECTS NOTED.