The SWM,steering wheel module has probably failed.
It is a circuit board mounted forward of the steering wheel
on the column.
The SWM will need to be loaded with new software.
Only a dealer or independent with VADIS can do this.
You could try this, remove both battery cables.
Touch the battery cable ends together for 5 seconds.
Reconnect cables and see if it helped.
Removing and touching the cable ends together
will reset all brains. The above will not erase any
stored fault codes.
Also the ABS brain can cause similar problems
because of the way the network signals run.
The path of information can and will pass through
other brains on its way to the proper brain.
BD