Power Steering Pressure Switch
The power steering pressure switch is mounted directly to the power steering gear. See Fig 1 . The power steering pressure switch is used to improve the vehicle's idle quality by causing a readjustment of the engine idle speed when increased fluid pressure is sensed in the power steering system. The pressure switch functions by signaling the Powertrain Control Module (PCM) that an increase in pressure of the power steering system is putting additional load on the engine. This type of condition exists when the front tires of the vehicle are turned while the vehicle is stationary and the engine is at idle speed. When the PCM receives the signal from the power steering pressure switch, it directs the engine to increase its idle speed. This increase in engine idle speed compensates for the additional load, thus maintaining the required engine idle speed and idle quality. The power steering pressure switch sends a signal to PCM when power steering pressure (load) rises to more than a predetermined pressure. When power steering load is high, such as during parking, PCM increases engine idle speed through IAC motor to prevent stalling.