A method to evaluate a secondary steering system including the steps of lowering the first hydraulic fluid pressure, determining the first hydraulic fluid pressure, sensing a second hydraulic fluid pressure, and comparing the first hydraulic fluid pressure to the second hydraulic fluid pressure. The lowering step includes lowering the first hydraulic fluid pressure provided by the primary steering system power source while the vehicle is traveling at a substantially predetermined speed. The sensing step includes sensing the second hydraulic fluid pressure provided by the secondary steering system power source while an operator of the vehicle is steering the vehicle as the vehicle travels at the predetermined speed. The comparing step includes comparing the first hydraulic fluid pressure to the second hydraulic fluid pressure to determine if the second steering system power source provided fluid to steer the ground-engaging device.