I'm reasonably sure it's actually the isolation washer in the steering column that absorbs vibrations between the electric steering motor and the column itself. I had to replace it on my 2013 last year.
You can read through the whole thread, or start around
here for the gist of things.
Ermax also made a good DIY thread.
When I took it in the tech traced it to the column, but at the time the only fix was to replace the entire steering column (for 1800 bucks or so). The actual fix is the just the washer which is a $10 part.