Steering wheel rattle mk4

[exim]

Anybody experienced the steering wheel rattling on the mk4 Yaris? It's a sort of staticky jittery sound/vibration that seems to happen mostly when driving on an incline.

Wasn't sure where it was coming from until I pressed in on the steering wheel and it would temporarily stop, so definitely coming from there. 

I tried adjusting the wheel steering position and it seemed to get worse.

Will be due for it's service soon, so will mention the problem then, but just wondering if it's a known thing.

[CPN]

There are various elements of the Toyota Safety Sense system that use vibration of the steering wheel to warn you of something? Were you aware of this? What were you actually doing when you felt it?

(for one example of it, see page 227 of the e-manual)