Service diagnostic found that the system was low on refrigerant. I also found that the condenser fan motor showed signs of overheating. The air handler, evaporator coil, and blower wheel were also dirty. I performed a leak check and did not find a leak in the system. Options for repair were presented to the homeowner and she chose to have refrigerant added to the system. I added two lbs of R-410A to the system and brought the sub cooling up to manufacture specifications of 12 degrees. The system was running and cooling with a 19 degree temperature split at the completion of service.