Power Steering Pressure Switch: Description
WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.
On vehicles equipped with a 2.0L four cylinder engine, a power steering pressure switch is used to improve the vehicle's idle quality when required (Other four cylinder engine models use a virtual power steering switch (VPSS) built into the vehicle's electronics). When a demand for power assist is put on the power steering system at idle, pump pressure puts additional load on the engine, thus decreasing engine idle speed. The pressure switch improves vehicle idle quality by maintaining the required engine idle speed when the pressure rises in the power steering system. See Figure.
The power steering pressure switch is mounted directly to the power steering gear. See Figure.