Variable Effort Steering Description

The variable effort steering (VES) system varies the driver effort that is required to steer as the vehicle speed changes. At low speeds, the system provides maximum power assist for easy turning and parking maneuvers. At higher speeds, steering effort is increased in order to provide the driver with firmer steering (road feel) and directional stability. The VES system varies the driver effort by reducing the power steering fluid flow from the pump as vehicle speed increases. When the vehicle is stationary, the system provides maximum flow. As the vehicle speed increases, the fluid flow is decreased.

The VES system consists of the following power steering components:

• The speed sensitive power steering (SSPS) control module
• The electronic variable orifice (EVO) actuator
• The steering wheel position sensor
• The power rack and pinion
• The power steering pump