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.
SPS P-Valve
SPS P-valve is located on steering gear housing and controls steering wheel torque between 0-50 MPH on CL500, S320, S420 and S500 or between 0-63 MPH on E300D, E320, E420 and E430. SPS P-valve is actuated in cycles by ETS, ASR V or ESP control module. As vehicle speed increases current flow reduces and SPS P-valve opens control restrictor continuously in accordance to parameters defined in the control module. Oil flow and steering wheel torque is controlled. If valve is fully energized, the control restrictor is closed, no oil flows and lowest steering wheel torque is adjusted (parking situations).
Use the Manual With the Right Hardware
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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.