Checking Venting System For Fuel Tank

CHECKING VENTING SYSTEM FOR FUEL TANK





- Check connections on expension tank for tight fit and leaks

1 Pipe to outdoors
2 Pipe to filler neck
3 Pipe to fuel tank





- Check connection for venting pipe.





- Checking routing and flow of vent hose.





- If applicable. remove and install / check tank venting valve.

M 10





1 = Carbon canister
2 = Check valve

M 20





1 = Carbon canister
2 = Tank venting valve

- Lift out plug for all previously mentioned models.
- Pull off hoses.
- Lift out tank venting valve.





- Connect vacuum hose (1) on 0.8 mm (0.031") diameter neck.
- Supply 12 V voltage to tank venting valve (2) (lead 61 1 440).





- Select multimeter function 21 on BMW Service Tester.
- Adjust vacuum to 600 +/- 100 mbar, then switch off.
- Pressure should not drop by more than 50 mbar during the test time of about 20 seconds.
- Replace tank venting valve, if pressure drops by more than 50 mbar.