Power Steering Pressure (PSP) Switch: Notes
WARNING: This page is about a different car, the 2004 Hyundai Santa Fe and 2003 Hyundai Santa Fe. However, it is still accessible from the selected car via links, so may be relevant.
The power steering oil pressure switch senses the power steering load and inputs it to PCM, which then adjusts the idle speed control motor to maintain idle speed when the power steering pump puts a load on the engine.
Courtesy of HYUNDAI MOTOR CO.