As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ANTI ICE DUCT WARNING MESSAGE ON APPROACH IN ORD FOLLOWED BY AN ANTI ICE DUCT CAUTION MESSAGE. RAN QRH, TRIED TURNING WING ANTI ICE BACK ON PER QRH AND SYSTEM SEEMED TO OPERATE NORMAL. (FLT#3059) CLOSED COULD NOT DUPLICATE. PERFORMED AILC SELF TEST TESTS GOOD. PERFORMED WING ANTI-ICE OPS CHECK, ALL INDICATIONS CORRECT AND LEADING EDGE TEMPS NORMAL IAW AMM.