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 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 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 and the second parameter value 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 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 and the second parameter value 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.