A method of determining a functional status of a steering system of a vehicle , the steering system including a rod to be coupled to a wheel (23a-b) of the vehicle and being arranged to turn the wheel under the control of a steering actuator operable to apply an actuation force (F) to the rod, the method including the steps of: acquiring a time sequence of sets of vehicle parameter values, each set of vehicle parameter values including a first parameter value (P 1 ) indicative of a desired change in a direction of travel of the vehicle, a second parameter value (P 2 ) indicative of a vehicle speed, and a third parameter value (P 3 ) indicative of the actuation force (F) currently applied by the steering actuator to the rod ; determining , for each set of acquired vehicle parameter values, based on the first parameter value (P 1 ), the second parameter value (P 2 ) and the third parameter value (P 3 ), a measure indicative of an observed strain (ε obs ) in the rod , between the steering actuator and the wheel (23a-b), resulting in a time sequence of measures indicative of the observed strain (ε obs ) in the rod; determining , for each set of acquired vehicle parameter values, based on the first parameter value (P1) and the second parameter value (P2) in the set of acquired parameter values, and a set of previously determined measurement values indicative of strain values for different values of the first parameter and the second parameter, a measure indicative of a predicted strain (ε pred ) in the rod , between the steering actuator and the wheel (23a-b), resulting in a time sequence of measures indicative of the predicted strain (ε pred ) in the rod; and determining the functional status of the steering system based on a relation between the time sequence of measures indicative of the observed strain (ε obs ) in the rod and the time sequence of measures indicative of the predicted strain (ε pred ) in the rod . acquiring a time sequence of sets of vehicle parameter values, each set of vehicle parameter values including a first parameter value (P 1 ) indicative of a desired change in a direction of travel of the vehicle, a second parameter value (P 2 ) indicative of a vehicle speed, and a third parameter value (P 3 ) indicative of the actuation force (F) currently applied by the steering actuator to the rod ; determining , for each set of acquired vehicle parameter values, based on the first parameter value (P 1 ), the second parameter value (P 2 ) and the third parameter value (P 3 ), a measure indicative of an observed strain (ε obs ) in the rod , between the steering actuator and the wheel (23a-b), resulting in a time sequence of measures indicative of the observed strain (ε obs ) in the rod; determining , for each set of acquired vehicle parameter values, based on the first parameter value (P1) and the second parameter value (P2) in the set of acquired parameter values, and a set of previously determined measurement values indicative of strain values for different values of the first parameter and the second parameter, a measure indicative of a predicted strain (ε pred ) in the rod , between the steering actuator and the wheel (23a-b), resulting in a time sequence of measures indicative of the predicted strain (ε pred ) in the rod; and determining the functional status of the steering system based on a relation between the time sequence of measures indicative of the observed strain (ε obs ) in the rod and the time sequence of measures indicative of the predicted strain (ε pred ) in the rod . <EOS>