Chart C-1C, Power Steering Pressure (PSP) Switch Check: Notes

PSP switch is normally open to ground, and ECM terminal will be near battery voltage. Turning steering wheel increases power steering oil pressure and its load on an idling engine. PSP switch will close before load can cause a poor idling condition. Closing PSP switch causes ECM voltage signal to read less than one volt. ECM will increase idle speed and prevent engine load stall.

1. Check for ECM signal voltage and for an open or a short to ground in Blue/White wire or for a faulty ECM.
2. Checks for a poor ground connection at the power steering pump and for a faulty PSP switch.