Fuel Gauge/Fuel Consumption

Using information about the quantity of fuel in the tank, injector open times and the speed of the car, the Electronic Display Unit (EDU) control module calculates the current and average fuel consumption and the range with remaining fuel.

Fuel level gauge
The EDU control module receives information about the remaining quantity of fuel from the fuel level sensor in the tank. Using this information, the control module controls the fuel gauge and the fuel warning lamp, which lights when the quantity of fuel in the tank goes below 10 l.

Fuel consumption
To calculate the current and average fuel consumption, the control module requires information about both the quantity of fuel injected and the distance driven.

The control module gets the quantity of fuel injected by measuring the pulse length of the injectors. If the car is equipped with Motronic, the EDU control module is linked by a lead to the 3rd injector. If the car is equipped with Trionic, the signal comes directly from the Trionic control module.

The control module calculates speed by measuring the pulse frequency from the speedometer.

Current fuel consumption
Current fuel consumption is calculated over a distance of about 10 meters.

On cars with a manual gearbox a bar indicator across the right-hand display shows the current fuel consumption.

Average fuel consumption
The average fuel consumption is calculated over the distance the vehicle has covered since the counters for "total distance covered" and "total fuel consumption" were last zeroed (R button pressed for more than 4 seconds). The display range is 0 to 99.9 liters/100 km, MPG Imp or MPG.