Power Steering Pressure Switch: Description and Operation

Wiring Diagram For P/S Switch:

The Power Steering Pressure Switch (PSPS) opens during high pressure power steering situations. When the power steering switch is open, circuit 495 reads battery voltage. This allows the ECM to increase the idle air rate and retard the ignition timing. A pressure switch that will not open, or an open circuit 495 or 450, may cause the engine to stall when the power steering loads are high. A switch that will not close, or a circuit 495 shorted to ground, may effect idle quality.