I think you might have hit the nail on the head there. From what your're saying it sounds like the 'slip ring' behind the steering wheel is faulting. The slip ring allows the electrics of the airbag and multi function steering wheel operate throughout the motion of the steering wheel. Ideally though you'll need to have the fault memory read to confirm this.
The part I have described can be seen as number 3 in this diagram.....
If you need anymore info please dont hesitate to ask.
Rich - How do I access the slip ring to see if it is faulty?
You will not be able to tell if it is faulty by looking at it im afraid, it is a long ribbon cable encased in a plastic cassette, it's a non serviceable item.
First you have to set the steering straight ahead and remove the airbag on the steering wheel. But before this you must disconnect the battery. There are 2 holes on the rear of the steering wheel with 27 torx screws inside, release these and the airbag will become free and you will be able to disconnect it. The airbag must be placed facing upwards when taken off.
There will now be other connectors visible in the centre of the steering wheel, disconnect these. If I remember rightly the bolt holding the steering wheel on is 16mm, release this. Before removing the steering wheel take note of the little score in the centre where the splined shaft is as it needs go back on in exactly the right position.
The slip ring will then be visible. Remove the surrounding steering column cowls and you will then be able to access the screws that hold it on. There will be a loom connected to the rear of the slip ring that needs to be disconnected.
The new slip ring comes set in an installation position so that is why the wheels must be in the straight ahead position. There is also a pin on the slip ring that located into a hole on the reverse of the steering wheel.
Rich - it sounds like I should take it to the dealership instead of trying to fix myself