Power Steering Pressure Switch: Description and Operation

The Power Steering Pressure (PSP) switch signals the powertrain control module (PCM) when the vehicle experiencing power steering assist. Turning the steering wheel causes increased power steering fluid pressure that closes the PSP switch. The PCM uses PSP switch signal in order to control the Idle Air Control (IAC) valve. In response to the PSP switch input the IAC valve increases the idle speed before the power steering load can cause a poor idling condition. The PSP switch is located in the power steering pump housing.