Displaying fuel quantity, function - GF54.30-P-3018PM
MODEL 203.0 /2 /7 as of 24.4.04
General
The fuel level and reserve indicator (A1p2) is located on the right hand side of the instrument cluster (A1) and is an analog display. The fuel level and reserve indicator (A1p2) is driven by a stepper motor.
Networking of components:
- The fuel level transmitter, left tank half (B4/1) and the fuel level transmitter, right tank half (B4/2) change their resistance according to the level of fuel in the tank. The fuller the tank the lower the resistance.
- The resistance of the fuel level sensor, left tank half (B4/1) and fuel level sensor, right tank half (B4/2) are 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 the resistance values of the fuel level sensor, left tank half (B4/1) and fuel level sensor, right tank half (B4/2) into a percent value, a full tank corresponds to 100 %.
- This percent value is placed on the Controller Area Network bus class B (interior) (CAN-B) by the rear SAM control unit with fuse and relay module (N10/2).
- The instrument cluster (A1) reads in this percent value from the CAN-B and evaluates it by means of a tank characteristic. With this value, calculated depending on the tank used, the fuel level and reserve indicator (A1p2) and where necessary the fuel reserve indicator lamp (A1e4) are activated accordingly.
Updating the fuel level and reserve indicator (A1p2) with "Circuit 15 ON"
With "Circuit 15 ON" the current tank content is displayed via the fuel level and reserve indicator (A1p2).
If the vehicle is refueled with "Circuit 15 ON", the fuel level and reserve indicator (A1p2) is only updated once the refueling quantity has reached approx. 7 l. The fuel level and reserve indicator (A1p2) is always updated with a delay period and the upwards movement of the pointer of the fuel level and reserve indicator (A1p2) is dampened. This prevents fluctuations in the fuel level and reserve indicator (A1p2) e.g. when cornering.
Updating the fuel level and reserve indicator (A1p2) with "Circuit 15 OFF"
If the vehicle is refueled with "Circuit 15 OFF", the fuel level and reserve indicator (A1p2) is updated as of a refueling quantity of approx. 3 l at the next "Circuit 15 ON".
Reserve indication range
When the reserve level is reached, the fuel reserve indicator light (A1e4) lights up in yellow when the engine is running. Actuation proceeds with a delay period to prevent flicker in the fuel reserve warning lamp (A1e4).
The tank contents are still approx. 7 l when the fuel reserve warning lamp (A1e4) lights up.
On vehicles with Code (494) USA version on which the filler cap is not closed the fuel reserve indicator lamp (A1e4) in the instrument cluster (A1) is actuated at a frequency of 2.5 Hz.
Fuel tank sensor tight installation recognition
As of a travel distance of greater than 160 km the fuel tank sensor tight installation recognition becomes active. Tight installation of the fuel tank sensor is recognized, if the resistance value of the left tank half fuel level sensor (B4/1) and/or the right tank half fuel level sensor (B4/2) does not change by at least a specified resistance value within a certain distance.
If this condition arises, a corresponding erroneous bit is set in the fault memory for the left tank half fuel level sensor (B4/1) and/or the right tank half fuel level sensor (B4/2). The respective bit is erased again once the required change in the resistance value of the left tank half fuel level sensor (B4/1) and/or the right tank half fuel level sensor (B4/2) has occurred.
The tight installation of the left tank half fuel level sensor (B4/1) and/or the right tank half fuel level sensor (B4/2) is entered into the fault memory of the instrument cluster (A1).
If a malfunction occurs the pointer in the fuel level and reserve indicator (A1p2) is moved to the to beginning of the scale. The fuel reserve warning lamp (A1e4) does not come on. The same applies if, due to implausible sensor values while driving, a tight installation of the left tank half fuel level sensor, (B4/1) and/or the right tank half fuel level sensor, (B4/2) is recognized.
| Instrument cluster (IC), location / task | GF54.30-P-3039PM |