Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Chart C-1E: P/S Pressure Switch
The power steering pressure switch is normally open to ground, and circuit No. 901 will be near the battery voltage (12 volts). Turning the steering wheel increases power steering oil pressure and its load on an idling engine. The pressure switch will close before the load can cause an idle problem. Closing the switch causes circuit No. 901 to read less than one volt and the ECM will increase the idle air rate and de-energize the A/C relay.
- A pressure switch that will not close, or an open in circuits No. 901 or 450, may cause the engine to stop when power steering loads are high.
- A switch that will not open, or a circuit No. 901 shorted to ground, may affect idle quantity, and will cause the A/C relay to be de-energized.NOTE: Test numbers refer to test numbers on diagnostic chart.
- Different makes of "SCAN" testers may display the state of this switch in different ways. Refer to "SCAN" tester to determine how this input is indicated.
- Checks to determine if circuit No. 901 is shorted to ground.
- This should simulate a closed switch.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.