Stratus V6-2.5L VIN H (1997)
Power Steering Pressure Switch: Description and Operation
Fig. 21 Power Steering Pressure Switch
PURPOSE
On some vehicles equipped with power steering, a power steering pressure switch is used to improve the vehicle's idle quality.
OPERATION
The pressure switch improves vehicle idle quality, by maintaining required engine idle speed when necessary, do to increased pressure in the
power steering system. This increased pressure will slow down the power steering pump which will decrease engine idle speed.
The pressure switch functions by signaling the power train 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.
The power steering pressure switch is mounted directly to the power steering gear on vehicle's requiring its usage.
When power steering pump pressure exceeds 4137 kPa (600 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.
CIRCUIT OPERATION
The power steering pressure switch opens and closes circuit K10 between the Powertrain Control Module (PCM) and ground. Circuit K10
connects to cavity 45 of the PCM connector.
Circuit Z1 provides a ground for the power steering pressure switch. The ground is terminated at the left strut tower.
