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.
1990 Ford Probe LX, AutomaticFACTORY OEM SERVICE PROCEDURE
Power Steering Pressure Switch (PSPS) Test
- Disconnect PSPS connector at steering gear box. Set DVOM to 200-ohm scale. Turn ignition switch to ON position. Measure resistance across PSPS terminals. Ohmmeter should indicate less than 10 ohms resistance between key on engine off and engine running.
- With engine running, turn steering wheel at least one-half turn then return. Resistance should change from less than 10 ohms to infinity (indicating PSPS opening), then returning to 10 ohms or less when steering wheel is returned to center position.
Factory Service Tools
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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.