What have you done before, just cleared the code? I also assume there's no other codes with it which might then indicate a fault?
It's a fuel trim code which simply means that something is causing your cars fuel trim range to be out of specs and that code does not point to any specific part which is why fault tracing that one can sometimes be more troublesome than most that indicate a bad part.

I'd check all vacuum hoses for cracks or deterioration at one (or more) ends if turbo, turbos hoses desolve at the ends due to normal oil mist in the lines.

Non-turbos tend to crack at the vacuum tree under the plastic throttle base cover or near that area.

Don't guess at expensive O2 sensors. Hopefully you didn't already.