Probably the same electronic DEVIL who lives in the auto gearbox and changes gears when your not even pressing the clutch or wiggling the gear-stick about
I thought it worked off the amount of fuel the tank level sensor is registering and calculates (based on previous and current driving / MPG ,fuel pulses ,RPM etc) how far you can go RANGE before you hand over a fist full of twenties at the petrol station
must be a sensor in the seat too to detect how fat your wallet is and adjusts the RANGE to slim your wallet to within selected tolerances (skint/empty)
I'm sure someone far more knowledgeable
will be along shortly Ah
The Good Doc has replied
In a nutshell...The engine and abs ecus.
The engine ecu knows what the injector duration is along with the fuel flow rate (system is set at 3.5 bar), and the abs gives speed/distance.
that then
still think there's a sensor in the driver seat though