Power Steering Pressure Switch: Description and Operation

POwer Steering Pressure (PSP) Switch Signal:

The Power Steering Pressure (PSP) switch (1) is located in high pressure line, near the power steering pump (2). The PSP switch signals the Powertrain Control Module (PCM) when the vehicle is experiencing power steering assist. Turning the steering wheel causes increased power steering fluid pressure that closes the PSP switch. The PCM uses the PSP switch signal to adjust 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 an engine idle quality concern.