A method for resetting a calibration of a sensor operating out of a prescribed range in a hydraulic actuation system, the hydraulic actuation system including: a pump arranged to supply fluid flow in response to a fluid flow demand; a reservoir arranged to hold fluid; a plurality of work-ports (32, 34, 68, 70), such that the pump is in fluid communication with the reservoir and the plurality of work-ports; a plurality of sensors (18, 24, 40, 48, 60, 76), each sensor arranged to sense pressure at a corresponding one of the plurality of work-ports (32, 34, 68, 70); a valve system (22, 38, 46, 54, 58, 74, 82, 88) arranged to control fluid flow between the pump, the reservoir and the plurality of work-ports (32, 34, 68, 70); and a controller arranged to regulate the pump and the valve system (22, 38, 46, 54, 58, 74, 82, 88) in response to the fluid flow demand and to the sensed pressures; the method comprising: detecting the sensor operating out of the prescribed range; relieving pressure in the hydraulic actuation system; opening all work-ports (32, 34, 68, 70) to the reservoir; sensing pressure at each sensor (18, 24, 40, 48, 60, 76); resetting all the sensors (18, 24, 40, 48, 60, 76) to a reservoir pressure; supplying all the sensors (18, 24, 40, 48, 60, 76) with the fluid at a maximum pump pressure; sensing the maximum pump pressure at each of the plurality of sensors (18, 24, 40, 48, 60, 76); determining an average pressure value across all sensors of the plurality of sensors (18, 24, 40, 48, 60, 76) whose sensed pressure is within the prescribed range of the maximum pump pressure; assigning the determined average pressure value to the sensor that is operating out of the prescribed range; and resetting the calibration of the sensor that is operating out of the prescribed range based on the reservoir pressure and the average pressure values. a pump arranged to supply fluid flow in response to a fluid flow demand; a reservoir arranged to hold fluid; a plurality of work-ports (32, 34, 68, 70), such that the pump is in fluid communication with the reservoir and the plurality of work-ports; a plurality of sensors (18, 24, 40, 48, 60, 76), each sensor arranged to sense pressure at a corresponding one of the plurality of work-ports (32, 34, 68, 70); a valve system (22, 38, 46, 54, 58, 74, 82, 88) arranged to control fluid flow between the pump, the reservoir and the plurality of work-ports (32, 34, 68, 70); and a controller arranged to regulate the pump and the valve system (22, 38, 46, 54, 58, 74, 82, 88) in response to the fluid flow demand and to the sensed pressures; the method comprising: detecting the sensor operating out of the prescribed range; relieving pressure in the hydraulic actuation system; opening all work-ports (32, 34, 68, 70) to the reservoir; sensing pressure at each sensor (18, 24, 40, 48, 60, 76); resetting all the sensors (18, 24, 40, 48, 60, 76) to a reservoir pressure; supplying all the sensors (18, 24, 40, 48, 60, 76) with the fluid at a maximum pump pressure; sensing the maximum pump pressure at each of the plurality of sensors (18, 24, 40, 48, 60, 76); determining an average pressure value across all sensors of the plurality of sensors (18, 24, 40, 48, 60, 76) whose sensed pressure is within the prescribed range of the maximum pump pressure; assigning the determined average pressure value to the sensor that is operating out of the prescribed range; and resetting the calibration of the sensor that is operating out of the prescribed range based on the reservoir pressure and the average pressure values. detecting the sensor operating out of the prescribed range; relieving pressure in the hydraulic actuation system; opening all work-ports (32, 34, 68, 70) to the reservoir; sensing pressure at each sensor (18, 24, 40, 48, 60, 76); resetting all the sensors (18, 24, 40, 48, 60, 76) to a reservoir pressure; supplying all the sensors (18, 24, 40, 48, 60, 76) with the fluid at a maximum pump pressure; sensing the maximum pump pressure at each of the plurality of sensors (18, 24, 40, 48, 60, 76); determining an average pressure value across all sensors of the plurality of sensors (18, 24, 40, 48, 60, 76) whose sensed pressure is within the prescribed range of the maximum pump pressure; assigning the determined average pressure value to the sensor that is operating out of the prescribed range; and resetting the calibration of the sensor that is operating out of the prescribed range based on the reservoir pressure and the average pressure values.