Control in "assist" position (page 3 of 3)

57M0060 A Reservoir Side Orifice B Hydraulic pressure in response to vehicle speed (Medium) C Feed D Feed Side Orifice E Pressure in reaction chamber F Reaction Chamber

As the car is driven, the rotors start turning and the fluid returns to the reservoir, reducing the fluid pressure at the gain control valve. Therefore, the gain control valve moves right, the orifice resistance on the pump and reservoir sides is appropriately balanced, with the result that the reaction chamber is in the medium range and the steering resistance is moderate.

57M0061 A Hydraulic pressure in response to vehicle speed (Low) B Feed C Return D Pressure in reaction chamber

When the car is moving at high speed, the sensor reduces the pressure further and the gain control valve moves right. The orifice pressure on the pump side is low and the pressure on the reservoir side is high, the fluid pressure in the reaction chamber is also high giving the steering wheel less assistance.