Power Steering Pressure Switch: Description and Operation
POWER STEERING PRESSURE SWITCHDESCRIPTION
On vehicles equipped with a 2.0L four cylinder engine, a power steering pressure switch (Fig. 16) 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.
The power steering pressure switch is mounted directly to the power steering gear (Fig. 16).
OPERATION
The pressure switch functions by signaling the powertrain control module that the power steering system is putting additional load on the engine. This type of condition exists when turning the front tires of the vehicle when the vehicle is stationary and the engine is at idle speed. When this condition is sensed by the power train control module, through a signal from the power steering pressure switch, engine idle speed will be maintained. The maintained engine idle speed compensates for the additional load, thus maintaining the require engine idle speed and idle quality.