Power Steering: Notes

The power steering system is a hydraulic assist to the mechanical linkage. The power steering system is equipped with an electronic variable orifice (EVO) integrated in the power steering pump. As the vehicle speed increases the EVO closes to reduce the hydraulic power assist to the steering system. The EVO is open at low speeds, and opens at high speeds when the steering wheel is turned rapidly, to increase the hydraulic power assist to the steering system.

The EVO on vehicles without air suspension interacts through a separate EVO module, on vehicles with air suspension the EVO interacts through the air suspension module.

The power steering system consists of:

• CIII power steering pump.
• Power steering fluid reservoir.
• Steering gear.
• Power steering fluid cooler.
• High and low pressure power steering hoses.
• Electronic variable orifice (EVO) actuator.