Scion 89438-33010 Power Steering Pressure Switch

The Power Steering Pressure Switch is located at the high-pressure line outlet fitting of the power steering pump. It closes and sends a signal to the PCM when steering system pressure reaches a high-pressure set point, which the PCM uses to maintain engine idle speed during parking maneuvers. If the engine stalls during parking or idles continuously at high rpm, the PSP switch's operation should be checked. To do so, disconnect the PSP switch connector and connect an ohmmeter to the terminals on the switch body. Start the engine and let it idle, turn the steering wheel to point the front wheels straight ahead, and read the ohmmeter. It should indicate no continuity (infinite resistance). Turn the steering wheel to either side, and the PSP switch should close as the wheel nears the steering stop on either side, and the meter should indicate continuity (zero ohms). If the switch fails either test, replace it. To replace the switch, raise the vehicle and support it securely on jack stands, disconnect the cable from the negative battery terminal, disconnect the electrical connector from the switch, and unscrew the switch from the fitting on the Rack And Pinion. Install and connect the new switch, lower the vehicle to the ground, and bleed air from the power steering system, adding fluid as required.