Genuine Fujitsu 9900190026 Outdoor Expansion Valve Coil is the expansion valve coil in the outdoor unit, the motor that opens and closes the valve to meter refrigerant flow as the board asks. A failed coil leaves the valve stuck, so the system loses that control and heats or cools poorly or stops with a fault. A genuine Fujitsu part is made to the same design as the original, so it goes back in the way the outdoor unit was built.