Checking fuel supply and tank ventilation systems for leaks: All:

• Remove cover in luggage compartment under luggage compartment floor (arrows).
Fig 1: Removing Cover In Luggage Compartment Under Luggage Compartment Floor
Courtesy of AUDI OF AMERICA, INC.
• Remove rear seat bench.

  See SEAT BENCH, REMOVING AND INSTALLING .

• Remove cover for connector flange on left and right sides (arrows).
Fig 2: Removing Cover For Connector Flange On Left & Right Sides
Courtesy of AUDI OF AMERICA, INC.
• Check whether seals under connector flanges are OK and whether lock rings and union nut of connector flange are properly tightened on fuel tank. Also check fuel line connections.
• Visually check all lines and hose connections of fuel supply system and replace leaking lines, e.g.:
  • Line from EVAP canister to Evaporative Emission (EVAP) Canister Purge Regulator Valve (in engine compartment)
  • Lines from EVAP canister to Leak Detection Pump (LDP)
  • Line from fuel tank to Evaporative Emission (EVAP) canister (under cover for EVAP canister)
  • Lines from EVAP system (under rear right wheel housing liner)
  • Fuel lines to engine
  NOTE:

  • Leaks at lines and components of fuel tank system can sometimes be located using a non-flammable, environmentally sound engine leak detection spray (e.g. G 001 800 A1).
  • Pressure of (max. 70 mbar) can be applied to the fuel system via the test connection (in engine compartment). Leaks can be determined using engine leak detection spray. When doing this, bubbles form at leaking areas.
• Repeat function test.

If malfunction persists:

• Visually check components of fuel supply system and EVAP system.
  • Fuel tank
  • EVAP canister
  • Leak Detection Pump (LDP) -V144-
  • Evaporative Emission (EVAP) canister purge regulator valve -N80-