Nissan Micra K12 Power steering without function – PS luminaire

Hello, a friend has a K12 in which for some time the PS / ESP lights in the instrument. Read out did not like the steering angle sensor any more. Now NISSAN the steering angle sensor is in the steering stick unit directly behind the steering wheel. I as everything apart but the winding coil for airbag, horn and steering wheel remote control is there nothing in it. So my guess that the LWS is sitting in the electric power steering under the instrument. therefore out of unit. Can I just install another one (the car has 81KW and at Ebay would just be a servo for a 1.5d in it). Does the dananch still have to be learned or programmed? Or is there a typical error that you can repair yourself (Bin Elektroniker)? A nice Sunday still. Would I be happy about every tip / help. The ladies doesn’t really have a lot of money on the Hohen Kenne for a expensive repair of your mobile kit.