Abstract: An electro-hydraulic steering system for an articulated machine includes an electrical circuit and a hydraulic circuit. The electrical circuit includes a controller, an electro-hydraulic valve assembly, and a spool position system. The hydraulic circuit includes a pump, at least one cylinder in selective fluid communication with the pump, and the valve assembly. The controller includes a computer-readable storage medium storing a steering system monitoring application which performs several steps. A desired flow of pressurized fluid to each cylinder and a desired spool position for the spool of the electro-hydraulic valve assembly, based upon the desired flow of pressurized fluid, are determined. The desired spool position and an actual spool position are compared to determine a spool-based flow error, which is summed over a period of time to determine a cumulative spool-based flow error. An event warning is issued when the cumulative spool-based flow error exceeds a threshold.