A steering system and method are described for a vehicle having steerable wheels, with steering of the wheels controlled, at least in part, by a valve assembly. A ground speed of the vehicle may be determined. Whether a steering command is being provided to a valve assembly may also be determined. An operational pressure at the valve assembly may be determined with a pressure sensor. A threshold pressure may be determined based upon the ground speed and/or whether a steering command is currently being provided. The operational pressure may then be compared with the operational pressure, and steering control with the valve assembly disabled based upon the comparison.