As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A MESSAGE"ELEVATOR SPLIT" DISPLAYED ON EOAP,DURING USE A/P CLIMB THOUGHT 16000FT.A/C AIR TURN BACK,PERFORMED TROUBLESHOOTING MAINTENANCE FOUND THE LEFT AND RIGHT CONTROL COLUMNS WERE DISCONNECTED.AFTER RECONNECTING THE DIVIDED TUBE AND INSPECTION OF THE CONTROL COLUMN AND ELEVATOR POSITION SENSORS, ALL OPERTION FUNCTION RETURNED TO NORMAL.