Upon arrival cooling system not functioning. Inspected outdoor system for error codes and circuit board displaying low pressure error code. Preceded to pressure the system with nitrogen and test connections with soap bubbles. Located refrigerant leak at the outdoor liquid line on the filter drier. Welded the coupling and pressured again to ensure leak was fully repaired. Evacuated system down to 500 microns. Charged system with fresh r410A refrigerant by weight and tested system. Adjusted charge to achieve proper sub cooling. System is fully operational at time of departure.