An apparatus (10) for helping to turn steerable wheels (12) of a vehicle comprises a hydraulic power-assisted steering gear (16). An electric motor (92) actuates the steering gear (16). A pump (84) supplies the steering gear (16) with hydraulic fluid. A vehicle speed sensor (102) senses vehicle speed and provides a vehicle speed signal. A controller (104) is responsive to the vehicle speed signal for controlling the pump (84). The controller (104) activates the pump (84) to supply hydraulic fluid to the steering gear (16) when the vehicle speed signal indicates a vehicle speed below a predetermined value and the controller (104) deactivating the pump (84) when the vehicle speed signal indicates a vehicle speed above the predetermined value.