MRS4RD Control Unit
The number of pins on the MRS4RD control unit has been increased from 50 (MRS4) to 75 because of the greater number of interfaces.
The MRS4RD control unit is located centrally in the vehicle on the transmission tunnel. Integrated in the MRS4RD control unit are two acceleration sensors set right-angles to one another. The linear acceleration sensor (X-axis) is positioned at 0 degrees to the vehicle's longitudinal axis, and the lateral acceleration sensor (Y-axis) at 90 degrees to that axis.
All acceleration sensors sense acceleration in two directions, i.e. they register both positive and negative acceleration. The polarity of the acceleration signals depends on the direction of impact. That means it is possible to distinguish between a front or rear impact and between a left or right side impact.