Power Steering Pressure Switch: Description and Operation

POWER STEERING FLUID PRESSURE SWITCH
On vehicles equipped with power steering, a Power Steering Pressure Switch is used to improve the vehicle's idle quality. The pressure switch improves vehicle idle quality, by controlling engine idle speed when required.

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 Powertrain Control Module through a signal from the Power Steering Pressure Switch, engine idle speed is increased. This increase in engine idle speed compensates for the additional load, thus maintaining the require engine idle speed and idle quality.

When power steering pump pressure exceeds 2758 kPa (400 psi), the switch is open. The PCM increases idle air flow through the IAC motor to prevent engine stalling. When pump pressure is low, the switch is closed.

Power Steering Pressure Switch:

The Power Steering Pressure Switch is mounted directly to the power steering gear.