Fuel supply and tank ventilation systems, checking for leaks
NOTE:
- The following describes individual areas in the fuel supply and ventilation systems where leaks are possible. After repairing a possible leak, perform a leak test to ensure that leak was successfully repaired.
- Switch off ignition.
- Check whether fuel filler cap was completely sealed for test.
- Check whether fuel filler cap seal was damaged or crimped. Replace if necessary.
Sedan:
- Remove carpeting in luggage compartment.
- Fold forward right rear seat backrest, if necessary.
Wagon:
- Remove left 1/3 backrest →
- 72 - SEAT - FRAMES
- 72 - SEAT - FRAMES for BODY INTERIOR - CABRIOLET
- Remove left side luggage compartment trim and dirt tray →
- 70 - INTERIOR TRIM
- 70 - INTERIOR TRIM for BODY INTERIOR - CABRIOLET
All models:
- Unbolt cover for locking flange in luggage compartment - arrows -.
Vehicles with all wheel drive:
- Remove rear seat bench →
- 72 - SEAT - FRAMES
- 72 - SEAT - FRAMES for BODY INTERIOR - CABRIOLET
- Unbolt cover for locking flange, left and right - arrows -.
All models:
NOTE:
- Observe installation notes for locking flanges:
- Vehicles with front wheel drive up to 06.03 Installing ;
- Vehicles with front wheel drive from 07.03 to 10.04 Installing ;
- Vehicles with front wheel drive as of 11.04: Installing ;
- Vehicles with all wheel drive up to 06.03 Right Installing , left Installing ;
- Vehicles with all wheel drive from 07.03 to 10.04: Right Installing , left Installing ;
- Vehicles with all wheel drive as of 11.04: Right Installing , left Installing .
- Check whether seals under locking flanges are OK and lock rings are properly tightened on fuel tank. Also check fuel line connections.
- Visually check all wires 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 N80 (in engine compartment).
- Lines from EVAP canister to Leak Detection Pump (LDP) V144.
- Line from fuel tank to EVAP canister (below cover for EVAP canister).
- Lines for tank ventilation (beneath right rear wheel housing liner).
- Fuel lines to engine.
NOTE:
- Leaks at lines and components of tank system can sometimes be located using a non-flammable, environmentally compliant leak detection spray. For this, initiate leak diagnostic several times in sequence to build up pressure in the system. At leaking areas, bubbles will form.
- Visually inspect fuel system components and tank ventilation system:
- Fuel tank
- EVAP canister
- Leak detection pump (LDP) V144
- Evaporative emission (EVAP) canister purge regulator valve N80
NOTE:
- Because of shape or function of these components it is not always possible to find leaks by applying spray. It may be necessary to clamp off the relevant component using hose clamps up to diameter 25 mm 3094 and initiate leak detection diagnostic. If the leak is no longer detected, the component that was clamped off is faulty. If clamp is placed directly on the diagnostic pump and a leak is still detected, then the diagnostic pump itself is leaking