Replacing Fuel Pump In Audi A4: Step-By-Step Guide

Replacing the fuel pump in an Audi A4 is a moderately difficult task that can be completed at home if you are handy. The fuel pump is located underneath the rear seat of the car. Before starting, ensure that your fuel tank is less than a quarter full to prevent fuel spillage. You will need a range of tools, including a flat-blade screwdriver, electrical wire insulation stripper, ratchet, and various sockets. The process involves removing the rear seat, disconnecting the fuel pump electrical connections and fuel lines, and carefully prying out the old fuel pump before installing the new one and reconnecting all lines and wiring.

Ensure your Audi A4 has less than a 1/4 tank of fuel

It is recommended to ensure that your Audi A4 has less than a 1/4 tank of fuel when replacing the fuel pump. This is because the fuel pump is located underneath the rear seat of the car, and the tank is designed in such a way that if there is more than a 1/4 tank of fuel, you will cause a fuel spill inside your passenger compartment when removing the rear seat. Therefore, it is important to ensure that your Audi A4 has less than a 1/4 tank of fuel before attempting to replace the fuel pump.

To check the fuel level in your Audi A4, you can look at the fuel gauge on the dashboard. The fuel gauge will indicate the approximate level of fuel in the tank. If the needle is in the first quarter of the gauge, then you have less than a 1/4 tank of fuel. If the needle is above this point, you will need to remove some fuel before proceeding with the fuel pump replacement.

There are a few ways to remove fuel from your Audi A4. One way is to simply drive the car until the fuel level drops below the 1/4 tank mark. Another way is to use a fuel transfer pump to remove the fuel from the tank and store it in a safe container. You can also use a siphon hose to manually remove the fuel from the tank. It is important to dispose of the fuel in a safe and environmentally friendly manner.

Once you have confirmed that your Audi A4 has less than a 1/4 tank of fuel, you can proceed with the fuel pump replacement. This job should be performed in a well-ventilated area to avoid inhaling fumes, and away from any sources of open flames to prevent fires. It is also recommended to disconnect the battery before beginning the fuel pump replacement to reduce the chance of a fire.

Disconnect the rear seat

Disconnecting the rear seat of an Audi A4 is a crucial step in accessing the fuel pump for replacement. Here is a detailed guide on how to do it:

Step 1:

Firmly pull up on the front edge of the rear seat, yanking it at the 1/4 and 3/4 points across its width to release the connectors. If your Audi A4 has rear seat heaters, carefully lift the rear seat bottom to locate and disconnect the wires.

Step 2:

Remove the rear seat bottom by pulling it out of the car and setting it aside. This will grant you easier access to the fuel pump area.

Step 3:

Locate the fuel pump cover, which is usually found on the passenger side, beneath the seat. This cover is secured by three Phillips head screws, which need to be removed.

Step 4:

Once the screws are removed, carefully lift and remove the cover plate. Underneath, you will find the fuel pump assembly head.

Step 5:

At this point, you may want to clean the area around the fuel pump head using compressed air, a vacuum, or similar tools to prevent debris from falling into the tank.

Step 6:

If your Audi A4 is equipped with rear seat heaters, carefully disconnect the seatbelt wires and heated seat wires from the connectors. Ensure that all electrical connections at the rear of the seat are disconnected before proceeding.

Step 7:

With all the connections disconnected, you can now remove the rear seat completely. This will provide full access to the fuel pump and the surrounding components for replacement or further maintenance.

Remember to exercise caution and wear appropriate protective gear when working on your vehicle. Ensure that you have less than a quarter tank of fuel before beginning this process to avoid fuel spillage.

Disconnect the pump

Disconnecting the pump is a crucial step in replacing the fuel pump in your Audi A4. Here is a detailed guide on how to do it:

Step 1: Identify the pump cover. This is located on the passenger side, beneath the rear seat cushion. If your car has rear seat heaters, carefully lift the rear seat bottom to access the wires and disconnect them.

Step 2: Remove the pump cover. You will need a Phillips-head screwdriver for this step. There are three screws holding the plate in place. Once removed, you will see the fuel pump assembly head.

Step 3: Disconnect the electrical connector from the fuel pump head. This is a standard Audi push-squeeze-pull connector. Be careful when disconnecting, as it may be sticky and require gentle prying to release. Cover the connector with a disposable glove and secure it with a rubber band to prevent fuel contamination.

Step 4: Disconnect the fuel lines. There will be a return line and a pressurized line. These are typically located at the 11 o'clock and 1 o'clock positions, respectively. They require a push, squeeze, and pull action to disconnect. Be careful not to damage the fuel lines, as they will need to be reconnected later.

Step 5: Relieve any built-up pressure in the fuel system by opening the fuel filler cap. This will help ensure that fuel does not spray out when you disconnect the fuel lines.

Step 6: Disconnect the fuel lines from the fuel pump. Use modified needle-nose pliers or small flat-tip screwdrivers to squeeze the side catches and then pull up on the fuel lines to disconnect them from the fuel pump head. Be gentle, as the fuel lines can be brittle.

Step 7: With the fuel lines and electrical connections disconnected, you can now remove the fuel pump. Use a flat-blade screwdriver and a dead blow hammer to rotate the fuel tank cover trim ring counter-clockwise to release it. Gently pry the fuel tank cover up to access the fuel pump.

Step 8: The fuel pump is held in place by tabs that lock it into the fuel tank basket. To remove the fuel pump, rotate it counter-clockwise to unlock it from the basket. Audi offers a special fuel pump removal tool, but it can also be carefully removed without this tool.

Step 9: Once the fuel pump is rotated counter-clockwise, lift it straight up and out of the vehicle. Be prepared to catch any remaining fuel in the pump with a small bucket or container.

Remember to work in a well-ventilated area when performing this task, as you will be exposed to gas fumes. Ensure that your vehicle has less than a quarter tank of fuel to avoid spillage inside the passenger compartment.

Remove the pump

The fuel pump is located underneath the rear seat. To access the pump, first, pull up on the front side of the seat to unseat the clips from the body. Then, disconnect the seatbelt wires and heated seat wires (if equipped) at the connectors. Now, remove the rear seat.

You will now see two covers on either side of the chassis. The cover on the passenger side houses the fuel pump and fuel level sending unit. Remove all three screws with a Phillips screwdriver and gently remove the cover.

At this point, you will have access to the top of the fuel tank. It is recommended to clean this area to prevent any dirt or debris from falling into the fuel tank during the removal process.

Disconnect the electrical connections and move them aside. Disconnect the two chassis fuel lines by pushing the round side inward and pulling up on the line. This will release the lock on the tab within the fuel tank cover. Be gentle, as these lines can be brittle.

Now, use a flat-blade screwdriver and a dead blow hammer to rotate the fuel tank cover trim ring counter-clockwise to relieve pressure on the seal. Gently pry the fuel tank cover up to access the fuel pump and inner fuel tank.

The fuel pump electrical connections and fuel supply line are connected to the underside of the fuel tank cover. The fuel supply line is difficult to remove and requires one-time-use connectors. The fuel pump can be removed with the fuel tank cover still attached via the wires and fuel supply line.

There are tabs along the outside of the fuel pump that lock it in place with the fuel tank basket. To remove the pump, rotate it counter-clockwise to unlock it from the fuel tank basket. Audi makes a special fuel pump removal tool, but it can also be carefully removed without this tool using a flat-blade screwdriver and a hammer.

Insert the screwdriver into one of the reliefs on the outer ring of the fuel pump and gently tap with the hammer. It only takes a small amount of force to move the fuel pump. Once the pump rotates counter-clockwise by about a centimetre, it can be lifted straight out and removed from the vehicle.

Install the new pump

Now that you have removed the old fuel pump, it is time to install the new one. Place the lower portion of the new fuel pump into the fuel tank, leaving the upper portion off to the side. Be careful not to damage the fuel level sender or get it stuck somewhere, as this may cause issues with registering the fuel level once everything is back together.

Reconnect the two pipes inside the tank that you disconnected earlier (the green and red arrows in Figure 4). Ensure that the top part of the fuel pump and the bottom part are firmly together. Maneuver the new tank gasket over the top of the fuel pump head and fit it to the fuel tank with the ribbed side up.

Place the fuel pump head back into the hole and ensure it is secure on the seal. Place the fuel pump ring back on the fuel pump head, orienting it as you took it off. Tighten the ring down so it is back in its position. Reattach the two lines and wiring securely (Figure 5).

Before installing the pump cover, prime the pump and fuel system. Reconnect the battery. Turn the key to the 'on' position without trying to start the car. You should hear the pump run briefly. Bump the starter by turning the key over to the start position just briefly without trying to start. You should hear the pump run again. Do this several times to ensure the pump is primed.

Once you have primed the pump, attempt to start the car. It may still take a little to get the system fully primed. Once started and there are no leaks or issues, reinstall the fuel cover plate. Reinstall the rear seat. Remember to reattach the rear seat heaters if your car is equipped with them.

Frequently asked questions