SPS P-Valve
WARNING: This page does not describe the selected car, but rather 26 other vehicles, including the 1999 Mercedes-Benz SLK230, 1999 Mercedes-Benz ML430, 1999 Mercedes-Benz ML320, 1999 Mercedes-Benz E430, and 1999 Mercedes-Benz E320. However, it is still accessible from the selected car via links, so may be relevant.
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).