Leak Test on Fuel Tank and Tank Ventilation System - I

Conducting Leak Test On Fuel Tank And Tank Ventilation System


NOTE:
The following procedure is only applicable to vehicles with the tank leak diagnosis module (DM-TL).
- Select "4 Expert mode" function on Diagnosis and Information System (DIS).
- From the menu "2 Activate components", select the function "118 Tank leak diagnosis E53: DMTL pump". Following appears in display: DMTL pump; pump is activated.
- Tank leak diagnosis pump pressurizes fuel tank and tank venting system.
For vehicles without tank leak diagnosis module: Pressurize through filler neck.
When leak-testing with a leak detector: follow manufacturer's operating instructions.


CAUTION:
On vehicles with tank leak diagnosis modules (DM-TL), do not work with external pressurization as the tank venting system will leak under this condition.
On account of emerging fuel vapors, carry out all work in well ventilated rooms. Or use a suitable extractor system. Observe country-specific accident prevention and occupational safety regulations.







The leak test can be carried out with a leak detector. Possible causes may be:
- Tank cap leaking (check tank cap pressure relief valve).
- Tank venting lines leaking (fuel tank - carbon canister - tank venting valve).
- Tank venting valve leaking (engine compartment)
- Fuel level sensor flange on tank leaking