Power Steering Pressure Switch: Description and Operation

Power Steering Pump High Pressure Switch:

This switch senses the pressure of the power steering system and works in conjunction with the ECU to adjust the engine rpm when the engine load is high and the rpm are low (i.e. when the vehicle is being parked).

When the power steering system pressure exceeds 1896 kPa +/- 172 kPa (275 psi +/- 25 psi) the ECU will increase the idle rpm via the Idle Speed Actuator (ISA) Motor so that the engine will not stall.

The power steering pressure switch and A/C control output lines are routed together to the ECU. This means that the idle speed will be raised, via the ECU and ISA motor, if the A/C is turned on and/or if the power steering system pressure exceeds 1896 kPa +/- 172 kPa (275 psi +/- 25 psi).