Checking Fuel Tank & Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL) - Z8

For vehicles without tank leak diagnosis module, go to step 3. For vehicles with tank leak diagnosis module, go to next step.
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.
Select 4 EXPERT MODE function on Diagnosis and Information System (DIS). From menu, 2 ACTIVATE COMPONENTS, select function 127 ACTIVATION DMTL PUMP. DMTL PUMP appears in display. Pump is activated. Tank leak diagnosis pump pressurizes fuel tank and tank venting system.
On vehicles without tank leak diagnosis module, pressurize tank through filler neck. When leak-testing with a leak detector, follow manufacturer's operating instructions. On account of emerging fuel vapors, carry out all operations in well ventilated rooms, or use a suitable extractor system.
Possible causes of leaks may be:
- Tank cap leaking (check tank cap pressure relief valve). See FUEL CAP PRESSURE RELIEF VALVE TEST under FUEL EVAPORATION.
- Tank venting lines leaking (fuel tank, EVAP carbon canister or tank venting valve).
- Tank venting valve leaking (engine compartment).
- Fuel level sensor flange on tank leaking.