The gauge only works when the ignition is switched on.
When the needle reaches the reserve zone, the indicator lamp 
Link lights up in the instrument cluster display.
Link lights up in the instrument cluster display.The tank capacity of your vehicle is given in the Technical data section Link.
Caution!
Never run the tank completely dry. If there is an irregular fuel supply, misfiring can occur. This allows unburnt fuel to enter the exhaust system, which could cause overheating and damage the catalytic converter.