Fuel gauge: Notes
The fuel gauge shows how much fuel is in the tank. It consists of a fuel gauge in the main instrument unit and a level sensor in the tank.
The level sensor has a variable resistance, the value of which corresponds to the level of the float in the tank. The resistance increases with the fuel level. In an empty tank, the resistance is 60+/-2.6 ohms and in a full tank 390+/-6 ohms (370+/-6 ohms for US and CA).
The sensor is powered with 12 V from pin 9 (K12) through a 1.1 kohm resistor integrated in the main instrument unit. The sensor is grounded via main instrument unit pin 8 (K12).
The main instrument unit senses the resistance of the sensor and controls the current to the fuel gauge so that the position of the gauge needle corresponds to the sensor's resistance.
To give a more accurate reading at low fuel levels, the main instrument unit's control module switches to measuring fuel consumption when the fuel level in the tank is below 10 litres.
The main instrument unit's control module sends fuel level information out on the bus.