DTC P0550: Power Steering Pressure Sensor/Switch Circuit, DTC P0552: Power Steering Pressure Sensor/Switch Circuit Low Input, DTC P0553: Power Steering Pressure Sensor/Switch Circuit High Input: Wiring Diagram
WARNING: This page is about a different car, the 2004 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.