GF54.30-P-3018SK Fuel Quantity Display Function

GF54.30-P-3018SK Fuel Quantity Display Function
- up to model year 08

Component Identification:

The fuel level is conveyed to the driver via the fuel level and reserve gauge (A1p2).
The fuel level and reserve gauge (A1p2) is located in the tachometer (A1p5) and is designed as an analog display. The fuel level and reserve gauge (A1p2) is driven by a stepper motor.
The fuel level sensor (B4) changes its resistance corresponding to the tank filling level. The fuller the tank, the lower the resistance. The resistance of the fuel level sensor (B4) is read in by the rear SAM control unit with fuse and relay module (N10/2). The rear SAM control unit with fuse and relay module (N10/2) converts this resistance value into a percent value. A full tank corresponds to 100 %.
This percent value is placed on the Controller Area Network bus class B (CAN-B) by the rear SAM control unit with fuse and relay module (N10/2).

The instrument cluster (A1) reads in this percentual value and evaluates it by means of a tank characteristic. With this calculated value the fuel level and reserve gauge (A1p2) and, if necessary, the fuel reserve warning lamp (A1e4) is actuated accordingly.

Updating of the fuel level and reserve gauge (A1p2) with "terminal 15 ON"
With "terminal 15 ON" the current tank contents are displayed via the fuel level and reserve gauge (A1p2).
If the vehicle is refueled with "terminal 15 ON", the fuel level and reserve gauge (A1p2) is only updated after a replenishing quantity of approx. 7 l. The fuel level and reserve gauge (A1p2) is always updated with a delay period and a dampened run up of the fuel level and reserve gauge pointer (A1p2).

Updating of the fuel level and reserve gauge (A1p2) with "terminal 15 OFF"
If the vehicle is refueled with "terminal 15 OFF", with "terminal 15 ON" the fuel level and reserve gauge (A1p2) is updated from a replenishing quantity of approx. 3 l.

Reserve zone
When the reserve level is reached, the fuel reserve indicator light (A1e4) lights up in yellow when the engine is running. The actuation takes place with a delay period in order to prevent the fuel reserve warning lamp (A1e4) from flickering.
The tank contents are still approx. 7 l when the fuel reserve warning lamp (A1e4) lights up.