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

The Power Steering Pressure (PSP) switch is normally open to ground, and ECM terminal will be near battery voltage. Turning the steering wheel increases power steering oil pressure and its load on an idling engine. Pressure switch will close before the load can cause an idle problem. Closing the switch causes ECM voltage signal to read less than one volt. ECM will increase idle air rate and prevent engine load stall.

1. Checks for ECM signal voltage, and for open or short to ground in Blue/Orange wire.
2. Checks for poor ground at power steering pump and for faulty PSP switch.