The fuel pump in an Audi A4 moves the fuel in the gas tank down the fuel lines towards the engine. This pump is critical to the proper operation of the vehicle; if it's not working correctly, the engine will not get sufficient fuel and will stutter or not run at all. If this happens, then the fuel pump will need to be replaced with a new one, but first, the old one has to come out.
Open the boot. Pull out the carpeted floor liner on the inside then pull out the wooden panel below to expose the silver fuel pump cover near the back seat. Unbolt the access cover above the fuel pump with a 1/4-inch ratchet and socket.
Unplug the harness to the fuel pump. Take off the ring nut located around the centre of the fuel pump with a spanner wrench.
Disconnect the fuel lines running to the fuel pump with needle-nose pliers. Take off the flange and sealing ring from around the fuel pump.
Turn the fuel pump module counterclockwise then lift it out of the gas tank.
Never smoke or have an open flame nearby while you're working on the fuel system of a vehicle. If you do, you risk causing a fire and damaging yourself and the vehicle.