SPS electrically controlled centering, function - GF46.50-P-2400AA

MODEL 203 with CODE (213) Speed-sensitive power steering up to Model Year 8 

MODEL 209, 211 with CODE (213) Speed-sensitive power steering 

MODEL 215, 220 

MODEL 230 up to Model Year 8 

Function 

The electronic control system of the speed-sensitive power steering is integrated in the traction system control module (N47). A certain manual force (K) is set at the steering wheel according to the speed of the vehicle. As the speed of the vehicle increases, the manual effort (K) required to turn the steering increases at the steering wheel (up to 100 km/h).

The driving speed calculated by the traction system control module (N47) is assigned a nominal current in a characteristic map. This current is then set in the SPS solenoid valve (Y10) (proportional solenoid valve) and influences the oil flow (hydraulic reaction) within the rack-and-pinion steering, and thus the manual force (K) required at the steering wheel.

Fig 1: Graph Showing Manual Force Of Steering Wheel

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The actuation of the SPS solenoid valve (Y10) is pulsed. The current is regulated by pulse-width modulation of these pulses.

Fig 2: Graph Of Actuation Of SPS Solenoid Valve

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.