This lean code on both bank 1 and 2 are many a times due to dirty or defective MAF sensor or vacuum leak. Try to clean the MAF sensor with the correct cleaner for this application and check for vacuum leaks.
But if both the MAF and vacuum leaks checked out ok.THen the problem is related to fault in the fuel system.
It can be any thing like Fuel pump,Fuel filter,Fuel pressure gauge etc etc .
First check the fuel pump.If its faulty it needs to be replaced.
Still as you mentioned that lean code for both bank 1 and bank 2 comes up.Both of them wont fail together however a vacuum leak will cause the codes Easiest one to check which takes seconds once you remove the plastic tray on top of your engine is the crankcase breather pipe running from the crankcase to the manifold (beside your air-box) .
Its common for the pipe to split underneath allowing UN metered air into the system causing the check light and the car to run lean.
Jaguar brought out a much sturdier pipe and dealer sells loads.They are around GB£5
Heres the location of the pipe
Thanks. keep updated for any more query.you can rate this solution
and show your appreciation.