Fuel Supply System

Safety Precautions

Note the following when working on the fuel system:


• Fuel system is under pressure! Before opening system, place clean rags around the connection. Then release pressure by carefully loosening the connection.

• Vehicles with FSI engine: The engine section of the fuel system, after high pressure pump, is under extremely high pressure! When working on engine or fuel injection system, pressure must be relieved to residual pressure before opening high pressure components.

Carry out the following measures before starting work on the fuel supply:

The following steps should be taken before beginning work on the fuel supply system:


Place lighters, as well as lighters of others in the area, out of reach. The lighter can ignite fuel vapors.


Observe safety precautions when disconnecting the battery.

• Disconnect Ground (GND) cable at battery Ground (GND) terminal with the ignition switched off.

• Open fuel filler flap briefly and then close again.

If it is necessary to use testing and measuring devices on road tests, observe the following:


Distraction and improperly secured test equipment can lead to accidents.

There is a risk that the passenger airbag could deploy in a collision.

• Operating testing and measuring equipment while driving creates a distraction.

• There is an increased risk of injury due to unsecured testing and measuring equipment.

• Always secure testers on the rear seat with a strap and have a second person on the rear seat operate them.

Note the following when removing and installing components from a filled or partially filled fuel tank:

• The fuel tank may only be partially full. How much fuel can remain in the fuel tank may be read in the respective work description. Empty fuel tank if necessary. Refer to => [ Fuel Tank, Draining ] Fuel Tank, Draining.

• Before starting work, switch on exhaust extraction system and place an extraction hose close to the installation opening of fuel tank to extract escaping fuel fumes. If no exhaust extraction system is available, a radial fan (as long as motor is not in air flow) with a displacement greater than 15 m3/h can be used.

• Prevent fuel from contacting skin! Wear fuel-resistant gloves!

Note the following when removing and installing the fuel tank:

• Fuel tank must be empty for weight reasons. Empty fuel tank if necessary. Refer to => [ Fuel Tank, Draining ] Fuel Tank, Draining.