The power steering pump is a vane-type design. The submerged pump has a housing and internal parts that are inside the reservoir and operate submerged in oil.

Install the Electronic Variable Orifice (EVO) actuator assembly at the rear of the pump. This assembly contains the electronic solenoid which controls the fluid flow to the steering gear. A pressure relief valve is installed inside the pump. This valve limits the maximum pump pressure. The pressure relief valve inside the flow control valve limits the pump pressure. Vehicles that are 15,000 GVW (RPO C5B) do not have an EVO actuator assembly on the power steering pump. These pumps have a discharge fitting at the rear of the pump. The pressure relief valve is installed inside the pump. This valve limits the maximum pump pressure.