Steering-Angle Sensor and DSC Sensor

The steering angle sensor and DSC sensor (DSC = Dynamic Stability Control) supply signals for the adaptive headlights to the adaptive headlights control unit. These signals are evaluated as follows, depending on the vehicle's speed:

• Vehicle speeds up to 30 km/h: 

  The adaptive headlights function is controlled using the information from the steering angle sensor (in the steering column switch cluster).

• Vehicle speeds between 30 km/h and 50 km/h: 

  In the 30 to 50 km/h speed range, there is a continuous transition in signal evaluation: from the evaluation of signals sent by the steering angle sensor to evaluation of the signals sent by the yaw-rate sensor (in the DSC sensor).

• In extreme dynamic driving situations  , e.g. if the vehicle starts to skid or fishtail, even at speeds less than 50 km/h  , the signals from the yaw-rate-sensor are considered.

  If the vehicle starts to skid or fishtail, the headlights will move to the straight - ahead position. The headlights are not moved until the vehicle has stabilized.

• Vehicle speeds over 50 km/h: 

  At speeds upwards of 50 km/h, the signals from the yaw-rate sensor  (in the DSC sensor) form the primary basis for control of the adaptive headlights function.

  Reason: For a constant cornering radius, the steering angle required increases disproportionately with speed. In addition, the steering angle required also depends on the coefficient of friction of the road surface.

  Yaw rate is directly proportional to speed. For this reason, the yaw rate is always the most suitable measure for controlling the adaptive headlights at high speeds.

  Even at high speeds, however, the steering angle sensor signal is used to detect (predict) the driver's commands in advance.  This prediction is important: The yaw rate signal is not supplied until the vehicle has responded  to the steering wheel movement.

  The steering-angle sensor signal is disabled so that rapid, momentary steering adjustments do not affect the adaptive headlights function.

A number of control units are involved in the adaptive headlights system (see above: CAS: CAR ACCESS SYSTEM , EGS CONTROL UNIT OR REVERSING LIGHT SWITCH  and SZL: STEERING COLUMN SWITCH ). Depending on the model series and model version concerned, the adaptive headlights are actuated by the following control units: