I have a 55 plate wrx300 which has some kind of fault with fuel sensor. Its been on a diagnostic and its coming up with fuel level sensor or something like that. It clears the fault and the engine managmant light goes off but it just comes back on. The fuel level is reading rock bottom, with the orange light on when its full. What is the first thing i should change, ive been told it could be sender unit???? Is this part of fuel pump?

I need it sorting as im selling car.
Cheers guys.

 

bump