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Audi Workshop Service and Repair Manuals

Fuel supply, gas operation > < General repair instructions
Working on the fuel system
Working on the fuel system
When working on the fuel system note the following warnings:
  WARNING
The fuel system operates at extremely high pressure. This can cause injury.
t  The fuel pressure in the high-pressure section of the injection system must be reduced to a residual pressure prior to opening the system.
t  Wrap a clean cloth around the connection and carefully loosen the connection to allow the residual pressure to dissipate.
–  Procedure before opening high-pressure section of injection system → Rep. gr.24.
Observe the following to prevent injuries to persons and damage to the injection and ignition system:
t  Always switch off the ignition before connecting or disconnecting electrical wiring for the injection or ignition system or tester cables.
t  Always switch off ignition before washing engine.
t  Faults are stored in engine control units if electrical connectors were unplugged and engine was started: Generate readiness code in Guided Functions → Vehicle diagnostic tester.
  Caution
To prevent irreparable damage to the electronic components when disconnecting the battery:
t  Observe notes on procedure for disconnecting the battery.
t  Always switch off the ignition before disconnecting the battery.
–  Disconnect battery → Electrical system; Rep. gr.27.
Perform the following steps before starting to work on the fuel supply system:
  WARNING
Mobile phones can cause an explosion risk.
Ensure that any mobile phones are well clear of the workbay.
  Caution
Electronic components are susceptible to damage.
Observe notes on procedure for disconnecting the battery.
t  Disconnect battery → Electrical system; Rep. gr.27.
t  Briefly open filler cap for fuel tank and close again.
When removing and installing components from a full or partly full fuel tank, note the following:
t  Fuel tank must not be full. The amount of fuel which can be left in the fuel tank is indicated in the corresponding procedure description. Drain fuel tank if there is too much fuel in tank. Procedure for rest-of-world vehicles with front-wheel drive → Chapter, rest-of-world vehicles with four-wheel drive → Chapter, USA vehicles with front-wheel drive and four-wheel drive → Chapter.
t  Before commencing work, switch on exhaust extraction system and place an extraction hose close to the sender opening in the fuel tank to extract escaping petrol fumes. If no exhaust extraction system is available, a radial fan with a displacement of at least 15 m3/h can be used (the fan motor must be clear of the air stream).
t  Avoid skin contact with fuel. Wear fuel-resistant gloves.
When removing and installing the fuel tank, note the following:
t  Fuel tank must be empty to reduce weight. Drain fuel tank if there is too much fuel in tank. Procedure for rest-of-world vehicles with front-wheel drive → Chapter, rest-of-world vehicles with four-wheel drive → Chapter, USA vehicles with front-wheel drive and four-wheel drive → Chapter.
   

Fuel supply, gas operation > < General repair instructions