The power steering system is a closed loop system. The power steering system consists of the following four major components:
• | The power steering fluid reservoir. |
• | The power steering pump. |
• | The steering gear. |
• | The power steering fluid cooling pipe. |
The power steering fluid is drawn from the power steering fluid reservoir by the power steering pump via the reservoir hose. The power steering pump, being the primary fluid mover, pressurizes and moves the fluid through the system. The pump discharges through the gear inlet hose, which transports the pressurized fluid to the steering gear. After exiting the steering gear via the gear outlet hose, the fluid is cooled by going through a fluid cooling pipe located in the front of the vehicle behind the front fascia. Upon exiting the cooling pipe, the fluid returns to the reservoir.
The Variable Effort Steering (VES) system varies the drivers effort required to steer the vehicle at different speeds. At low speeds, the system provides maximum power assist for ease of turning and parking maneuvers. At higher speeds, increased steering effort will provide the driver with firmer steering (road feel) and directional stability.
The VES system accomplishes this by reducing power steering fluid flow from the pump as the vehicle speed increases. When the vehicle is stationary, the system provides maximum fluid flow. As the vehicle's speed increases, fluid flow will decrease.
The power steering control module uses vehicle speed input from the Electronic Braking and Traction Control Module (EBTCM) to control the power steering fluid flow control valve actuator. The power steering fluid flow control valve actuator utilizes a pintle valve to control the fluid flow to the steering gear. In the event of a failure, the system will default to a full restriction. A full restriction will result in stiffer than normal steering at lower speeds.