Function description:

Six function buttons are integrated into the steering wheel for better operation of the radio system. In addition, the multifunction steering wheel is electrically heated (optional).

The electronics integrated in the steering wheel take over the transmission of the six function buttons to CAN-bus and dimming of the function buttons. On vehicles with automatic transmission, 2 additional buttons can be installed for Tiptronic shifting function. The electronics in the steering wheel cannot be replaced individually, the entire steering wheel must be replaced in case of a fault. 

The multi-function steering wheel is part of the complete system "switch module-steering column (SMSC) and transmits its data to the Steering Column Electronic Systems Control Module -J527-.