Self-study programme no. 259 (VW Service Training, 2003) explains the design and function of the electro-hydraulic power steering (EPHS) used in the VW Polo 6R, supplied by TRW and KOYO. A gear pump driven by an electric motor replaces the engine-driven vane pump; the power steering control unit J500 sets the delivery from the steering angle rate, vehicle speed and engine speed. The document covers the engine pump assembly, the power steering sensor G250 (capacitive on TRW, Hall sensor on KOYO), the steering angle sender G85, restart protection, the hydraulic control unit, the function diagram, checking the fluid level and self-diagnosis (address word 44), with test questions at the end. The Polo 6C has electromechanical steering instead.