error fuel level reading

["R.Wiratorn" <withu@loxinfo.co.th>]

        Hi
                The digital on board computer of my S4 ( the one that calculate
        the distance the car can go with the amount of fuel left in the tank
) show
        "E" ( empty ) while the analog fuel gauge just reach the 1/2 point.
I refill
        the gas and I able to put 44 liters into the tank.
                The guy at dealer said that the on board computer is gone,
they change
        it and charge me $600...!!
                Why  isn't it as durable as I thought ? I'm just not sure
that it's really
        the right way to fix it. May be they change it because they don't
know what else
        could cause this problem. I'll see if it show "E" too soon again
with the new
        expensive computer.

                                                                            
    K.Ben