I have the same wheel(although I use a TX now), I was having problems with my wheel losing FFB & wheel control, Fanatec were very good although they couldn't find the fault at first(took 3/4 times sending the wheel), they finally reproduced the fault, this is the reply I had -
" I was testing your wheel again today and finally was able to reproduce the fault.
The reason was, that the cooling fans did not work and due to that the wheel was acting up.
I replaced the main-pcb again and also the codewheel-sensor as a precaution. Now everything works fine again. I will test your wheel again, but will presumably send it back today."
I received it back at all seems ok(although I don't use it anymore). So if I was you I would get onto Fanatec asap(if still in warranty), they still might be able to help