When I say calibrate, I mean exactly that. You are basically telling the dsc module where the zero point is. By zero point I mean wheel straight ahead. This is how dsc know wheel position for things such as traction control activation, bi xenon swivel module movement, etc.... (The signal for headlight movement is a bus signal from the vehicle gateway which is the kombi aka instument cluster)

Now say the wheel is far off center while driving..... The dsc control unit looks at the LEW( steering angle sensor) and sees the wheel turned, then compares it to individual wheel speeds(during turning one wheel moves faster than the other... And the control unit can also tell the direction of turn just from these signals as well)realizes that this is not plausible( conflicting data) then sets the steering angle sensor plausibility fault. Steering angle is used for a lot of things, on the new cars it is also used for dynamic cornering lights( curb lights), turn signal deactivation( seeing the wheel turn then return to center)