Durango 2WD V8-4.7L VIN N (2001)
Power Steering Pressure Switch: Description and Operation
DESCRIPTION
A pressure sensing switch is included in the power steering system (mounted on the high pressure line). This switch will be used only on vehicles
equipped with a 4.7L V-8 engine and power steering.
OPERATION
The power steering pressure switch provides an input to the Powertrain Control Module (PCM). This input is provided during periods of high pump
load and low engine rpm; such as during parking maneuvers. The PCM will then increase the idle speed through the Idle Air Control (IAC) motor.
This is done to prevent the engine from stalling under the increased load.
When steering pump pressure exceeds 3275 kPa ± 690 kPa (475 psi ± 100 psi), the normally closed switch will open and the PCM will increase the
engine idle speed. This will prevent the engine from stalling.
When pump pressure drops to approximately 1379 kPa (200 psi), the switch circuit will re-close and engine idle speed will return to its previous
setting.
