Removing and Installing Fuel Pump/Fuel Level Sender

GENERAL INFORMATION

On gasoline engines, the fuel pump together with the fuel level sender is located in the reserve fuel tank. On Audi A3 vehicles with diesel engines, fuel is drawn in by the injection pump, so the fuel tank contains only the fuel level sender. All-wheel drive vehicles have a two-part fuel tank due to the space occupied by the driveshaft. In this case, each of the two tank halves has its own fuel level sender. The electric fuel pump is located in the right tank.

The fuel level sender consists of a float and a potentiometer. As the fuel level drops, the float also drops. The potentiometer connected to the float increases the sender resistance. As a result, the voltage on the instrument panel decreases and the fuel gauge needle moves toward "Empty". On vehicles with a two-part fuel tank, the control module calculates the total fuel quantity based on the signals from both senders and controls the fuel gauge on the instrument panel.

CAUTION

Some fuel may leak out when the fuel pump is removed. Fuel vapors are toxic and flammable, so make sure the work area is well ventilated. Avoid skin contact with fuel. Wear fuel-resistant gloves. Do not use open flame. Risk of fire! Keep a fire extinguisher ready. Before removing the fuel pump and reserve sender, it is recommended to drain the tank. To ventilate the work area, a radial fan can be used, with its electric motor located outside the airflow.

REMOVAL

PROCEDURE

1. Disconnect the negative (–) battery cable with the ignition switched off.

CAUTION

As a result, information in the electronic memory modules, such as the radio code, will be erased. Without the code, the radio can only be activated by the manufacturer or an AUDI dealership. Therefore, refer to the section Entering the Radio Code.

2. Fold down the rear seat and remove the cover of the reserve fuel level sender and fuel pump.

CAUTION

The fuel system is under pressure! Before opening hose connections, place a thick rag over them. Then carefully open the hose and release the pressure. Wear safety glasses while doing so.

3. Disconnect the supply line –2– and return line –1–, squeezing the retaining tabs on the quick-release couplings. Seal the lines with plugs, for example a bolt with sealant.

4. Disconnect the connector of the reserve fuel level sender/fuel pump.

5. Unscrew the union nut using special tool AUDI–3217.

CAUTION

If the specified tool is not available, loosen the nut using a wooden block and light hammer blows. Never allow sparks to form.

6. Remove the pump unit/reserve level sender and the O-ring from the fuel tank opening.

7. Drain fuel from the pump unit into the tank or a suitable container.

8. If necessary, remove the reserve fuel level sender. To do this, disconnect wires –3– and –4–. Lift the retaining clips –1– and –2– with a screwdriver and remove the sender downward.

INSTALLATION

PROCEDURE

1. Insert the sender into the guides on the holder and press upward until it locks. Connect the electrical wires to the reserve fuel level sender.

2. Install the pump unit into the fuel tank. Make sure the reserve fuel level sender is not bent during installation. Moisten the O-ring with fuel before installing.

3. Check the position of the flange. The arrow on the cover must point in the direction of the arrow on the tank. Refer to the illustration.

4. Tighten the union nut using special tool AUDI–3217 to 60 N·m. The union nut can be tightened with light hammer blows through a wooden block.

5. Connect the supply and return hoses; the quick-release couplings must lock. Use new band clamps when securing. The return hose is blue, the supply hose is black. The arrows on the flange indicate the direction of fluid flow.

6. Connect the electrical connectors.

7. Secure the reserve fuel level sender cover.

8. Install the rear seat.

9. Connect the negative battery cable (–) to the battery.

CAUTION

Activate the anti-trap safety function of the power windows, enter the radio code, and set the clock. Refer to the section Entering the Radio Code.