In order to prevent stalling when power steering load becomes excessive, some engines use an oil pressure switch, attached to the power steering high pressure line, to detect the power steering load. When power steering load reaches a predetermined level, the switch closes, sending a signal to the control unit. The control unit will then send a command to the idle controlling device to increase idle speed. When steering loads return to normal level, the switch will open and the idle up command will cease.
See Figure 1
- Disconnect the PSP switch connector.
- Start the engine and allow to idle.
- Check for continuity between across the terminals.
- With the steering wheel straight, there should be no continuity. With the steering wheel being turned, there should be continuity between the terminals. If the switch does not perform as specified replace the switch and retest.
REMOVAL & INSTALLATION
- Partially drain the power steering fluid.
- Disconnect the wiring connector from the Power Steering Pressure switch (PSP).
- Remove the power steering pressure switch using 2 suitable wrenches to prevent twisting the pressure line.
- Plug the line opening with a clean rag to prevent entry of dirt or contamination.
- Install the power steering pressure switch with a new seal and tighten securely.
- Connect the wiring connector.
- Fill the power steering fluid to the proper level.
- Start the engine and turn the wheel right to left and check for leaks.
- Following proper procedures, bleed air from the power steering system.