As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 218 - AFTER TAKEOFF ORD WHEN LANDING GEAR RETRACTED, MFDU MESSAGE LEFT MAIN LANDING GEAR WITH NO OTHER ABNORMAL INDICATIONS. AIRCRAFT RETURNED ORD AND LANDED WITHOUT INCIDENT. REPLACED LEFT MAIN LANDING GEAR UPSTOP DAMPER. ACCOMPLISHED LANDING GEAR RETRACTION CHECK WITH NO DEFECTS FOUND. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)