ECO valve

NOTE: not in conjunction with EPS electromechanical power steering.

The power steering pump is a vane-type compressor. The ECO valve (ECO = Electronically Controlled Orifice) is located at the power steering pump. The ECO valve regulates the volumetric flow of the hydraulic fluid, thus regulating the pump's hydraulic power.

A tandem pump is installed on vehicles with Dynamic Drive. The radial pistons supply the active roll stabilization (ARS). The vane-type compressor supplies the steering.

The ECO valve in the power steering pump regulates the volumetric flow depending on the requirement and lowers the ram pressure in the hydraulic system. In this way, the ECO valve affects the power consumption of the power steering pump. Fuel consumption and carbon dioxide emissions (CO2) from the vehicle's engine are reduced accordingly.

Fig 1: Identifying ECO Valve Components

Courtesy of BMW OF NORTH AMERICA, INC.

Item	Explanation
1	two-pin plug connection
2	Servotronic valve
3	Tandem pump
4	Suction throttle valve