Note. The presence of air in the fuel system of the independent heater may lead to combustion process disturbances. To prevent air from being sucked in and supplied to the independent heater from the metering pump "V54" when the independent heater is first switched on after work has been performed on the fuel tank or on the fuel supply module, fill the fuel pick-up pipe with fuel after work has been performed on these elements (remove air). The following figure shows the arrangement of units and components for the Audi A5 Coupe, for the Audi Q5 there are minor differences in the arrangement of units/components from this figure. The fuel lines must be installed flush with the bottom of the car and protected from mechanical damage. The fuel line to the independent heater must be protected from excessive heat. The fuel line must not touch the hot or moving parts of the car. There must be no air in the fuel line going to the independent heater. The fuel tank is equipped with different fuel supply modules for cars with and without an independent heater. To prevent steam bubbles from collecting at the joints of the fuel line elements, they must be connected end to end.
1. Dosing pump "V54". Depending on the vehicle version, a silencer may be built into the fuel line going to the independent heater in the area of the dosing pump "V54" to reduce noise.; 2. Fuel supply module with a branch pipe for fuel selection for an independent heater. Various fuel supply modules, depending on the type of vehicle (petrol or diesel engine). Fill fuel into the fuel line of the metering pump "V54" (remove air); 3. Fuel line. To prevent steam bubbles from accumulating at the junctions of the fuel line elements, they must be connected end to end. Pour fuel into the fuel line of the metering pump "V54" (remove air); 4. Autonomous heater. Different versions depending on the time of manufacture, car model and engine type: petrol or diesel (for example, on the Audi Q5, it is not possible to install independent heaters with the number 8K0.xxx.xxx)