Fuel Level
The fuel level in the tank is measured by a sensor. The sensor is on the pump side of the fuel tank. The sensor is directly connected to the central electronic module (CEM) on the same side as the DC/AC converter (only applies to B4184S8).
There are different tables for different fuel tank sizes. The tables are stored in the central electronic module (CEM) and indicate which sensor values correspond to the remaining fuel in the tank. The central electronic module (CEM) determines which tank is in the car by reading a parameter.
The resistance of the sensor increases as the fuel volume in the tank decreases. The signal from the sensor is compared with the values in the fuel tank table to obtain a value for the remaining fuel volume. This data is displayed by the fuel gauge in the driver information module (DIM).
If the fuel level sensor is faulty, the fuel gauge will show 0.
There are diagnostics for the fuel level sensor. In the event of a fault on the DC/AC converter (only applies to B4184S8) any fuel level measurement functions are affected.