Driver assistance systems operating unit
Fig. 158: Identifying Driver Assistance Systems Operating Unit Buttons
INDEX REFERENCE CHART
The driver assistance systems operating unit contains a button for switching the collision warning on and off.
The operating unit is connected to the footwell module (FRM) on the LIN bus. A bus signal from the FRM notifies the ICM control unit when the button has been pressed.
Fig. 159: LIN Bus Subscribers At Footwell Module
INDEX REFERENCE CHART
BE_FAS - Driver assistance systems operating unit
FRM - Footwell module
The ICM does not allow the collision warning to switch on unless the entire system is working faultlessly. It is only then that a bus signal providing positive feedback is sent to the FRM in order to have the function illumination in the button light up. If, however, a fault is present in any part of the entire system, the function illumination remains off even if the button is pressed. From this, the driver can infer that the collision warning is not available.
Multifunction steering wheel button pad
Which version of the MFL button pad on the left-hand spoke of the multifunction steering wheel is fitted button pad on the right-hand spoke, which is the same regardless of whether the vehicle is equipped with DCC or ACC Stop&Go.
The operation and function of the buttons were described in the "functions" section.
Fig. 160: LIN Bus Subscribers At Steering Column Switch Cluster
INDEX REFERENCE CHART
MFL - Multifunction steering wheel
SZL - Steering column switch cluster
The electronics of the multifunction steering wheel evaluate the button strokes on both MFL button pads. On the LIN bus, the signals are transmitted to the steering column switch cluster (SZL). The SZL forwards the button stroke signals to the ICM control unit on the FlexRay. This is where the signals for controlling the DCC and ACC Stop&Go function are evaluated.
There is no function illumination on the MFL button pad. For this reason, no feedback is sent by the ICM control unit to the MFL button pad as it is to the driver assistance systems operating unit.